A single amino acid residue controls ROS production in respiratory Complex I from Escherichia coli. The researchers found that replacing a glutamate residue (E95) near the nicotinamide adenine dinucleotide (NADH)-binding site in the NuoF subunit dramatically increases the enzyme's reactivity toward dioxygen and ROS production. The E95Q variant exhibits strong artificial reduction of short-chain ubiquinones at the catalytic site, also leading to higher ROS formation. Two mechanisms may contribute: a change in the reactivity of flavin mononucleotide (FMN) toward oxygen, and a change in the population of the ROS-generating state. The study suggests Complex I may exist in closed
Transcriptome-wide changes in Chlamydomonas reinhardtii gene expression regul...Wei Fang
This document summarizes a study that used RNA sequencing to analyze changes in gene expression in the alga Chlamydomonas reinhardtii under different carbon dioxide (CO2) conditions and in a mutant lacking the CO2-concentrating mechanism regulator CIA5. The study found massive effects on the transcriptome, with almost 25% of genes affected. Distinct clusters of genes were identified that responded primarily to either CIA5 or CO2. Several clusters associated with CO2-concentrating mechanism genes were identified that may contain new candidate genes involved in inorganic carbon transport.
Free radicals are molecules with unpaired electrons that are highly reactive. They are generated through oxidative metabolism and reactions involving oxygen. Common free radicals include superoxide, hydroxyl radicals, and lipid peroxyl radicals. While free radicals can cause damage to tissues, the body has antioxidant defenses like superoxide dismutase, catalase, glutathione peroxidase, and vitamins C and E that help neutralize free radicals. Antioxidants protect cells from the harmful effects of free radical formation and oxidative stress.
This document discusses several topics in bio-inorganic chemistry including nitrogen fixation, nitrogenase, metal ion transport, transferrin, and ferritin. Nitrogenase is an enzyme that reduces nitrogen gas to ammonia and was first isolated in 1960. It contains iron and molybdenum cofactors. Transferrin transports iron in the blood by binding Fe3+ ions. Ferritin stores iron in tissues by encapsulating ferric hydroxide. The anticancer drug cisplatin works by binding to DNA and inhibiting replication through DNA crosslinking.
Free radicals are molecules with unpaired electrons that are highly reactive. They are generated through normal metabolic processes in the body and can cause damage. The body has antioxidant defenses against free radicals including enzymes like superoxide dismutase, catalase, and glutathione peroxidase which neutralize reactive oxygen species. Vitamins C and E also act as antioxidants to help prevent free radical damage to cells. While small amounts of free radicals occur naturally, excessive amounts from sources like pollution, smoking, or radiation can potentially cause harm if the body's defenses are overwhelmed.
Free radicals are atoms, molecules, or ions with unpaired electrons that make them highly reactive. They are formed through processes like homolysis and oxidation-reduction reactions. Free radical stability is determined by factors like conjugation, hybridization, and hyperconjugation which disperse and stabilize the unpaired electron. Common examples of stable radicals include molecular oxygen and organic radicals within conjugated systems.
This document discusses nitrogen metabolism in living organisms. It notes that nitrogen is an important component of amino acids, proteins, enzymes, vitamins, and hormones. While nitrogen gas (N2) makes up 78% of the atmosphere, most organisms cannot use it directly. The nitrogen cycle converts atmospheric nitrogen into usable forms through processes like nitrogen fixation. Nitrogen fixation involves reducing nitrogen gas into compounds like ammonia, which is an anaerobic process requiring reducing conditions. There are two types of nitrogen fixation - abiological fixation such as the industrial Haber process, and biological fixation where nitrogen-fixing bacteria convert nitrogen gas to ammonia using the nitrogenase enzyme.
Metalloenzymes contain metal ions that help catalyze important biochemical reactions. Antioxidants protect cells from oxidative damage caused by free radicals generated during normal metabolism and environmental exposures. There are many classes of antioxidants including vitamins, minerals, enzymes, carotenoids, flavonoids, and phenolic compounds. Antioxidants act as reducing agents that prevent oxidative chain reactions and thereby protect cellular components from oxidative damage.
The document discusses ruthenium-based drugs as potential alternatives to platinum-based anticancer drugs like cisplatin. Ruthenium compounds have properties that make them well-suited for medical applications, including ligand exchange kinetics similar to cisplatin and the ability to exist in multiple oxidation states under physiological conditions. Some ruthenium complexes have shown anticancer activity through interactions with DNA like intercalation and groove binding. The most successful ruthenium-based drug to date is NAMI-A, which can bind DNA but does not appear to cause DNA damage as its mechanism of action.
Transcriptome-wide changes in Chlamydomonas reinhardtii gene expression regul...Wei Fang
This document summarizes a study that used RNA sequencing to analyze changes in gene expression in the alga Chlamydomonas reinhardtii under different carbon dioxide (CO2) conditions and in a mutant lacking the CO2-concentrating mechanism regulator CIA5. The study found massive effects on the transcriptome, with almost 25% of genes affected. Distinct clusters of genes were identified that responded primarily to either CIA5 or CO2. Several clusters associated with CO2-concentrating mechanism genes were identified that may contain new candidate genes involved in inorganic carbon transport.
Free radicals are molecules with unpaired electrons that are highly reactive. They are generated through oxidative metabolism and reactions involving oxygen. Common free radicals include superoxide, hydroxyl radicals, and lipid peroxyl radicals. While free radicals can cause damage to tissues, the body has antioxidant defenses like superoxide dismutase, catalase, glutathione peroxidase, and vitamins C and E that help neutralize free radicals. Antioxidants protect cells from the harmful effects of free radical formation and oxidative stress.
This document discusses several topics in bio-inorganic chemistry including nitrogen fixation, nitrogenase, metal ion transport, transferrin, and ferritin. Nitrogenase is an enzyme that reduces nitrogen gas to ammonia and was first isolated in 1960. It contains iron and molybdenum cofactors. Transferrin transports iron in the blood by binding Fe3+ ions. Ferritin stores iron in tissues by encapsulating ferric hydroxide. The anticancer drug cisplatin works by binding to DNA and inhibiting replication through DNA crosslinking.
Free radicals are molecules with unpaired electrons that are highly reactive. They are generated through normal metabolic processes in the body and can cause damage. The body has antioxidant defenses against free radicals including enzymes like superoxide dismutase, catalase, and glutathione peroxidase which neutralize reactive oxygen species. Vitamins C and E also act as antioxidants to help prevent free radical damage to cells. While small amounts of free radicals occur naturally, excessive amounts from sources like pollution, smoking, or radiation can potentially cause harm if the body's defenses are overwhelmed.
Free radicals are atoms, molecules, or ions with unpaired electrons that make them highly reactive. They are formed through processes like homolysis and oxidation-reduction reactions. Free radical stability is determined by factors like conjugation, hybridization, and hyperconjugation which disperse and stabilize the unpaired electron. Common examples of stable radicals include molecular oxygen and organic radicals within conjugated systems.
This document discusses nitrogen metabolism in living organisms. It notes that nitrogen is an important component of amino acids, proteins, enzymes, vitamins, and hormones. While nitrogen gas (N2) makes up 78% of the atmosphere, most organisms cannot use it directly. The nitrogen cycle converts atmospheric nitrogen into usable forms through processes like nitrogen fixation. Nitrogen fixation involves reducing nitrogen gas into compounds like ammonia, which is an anaerobic process requiring reducing conditions. There are two types of nitrogen fixation - abiological fixation such as the industrial Haber process, and biological fixation where nitrogen-fixing bacteria convert nitrogen gas to ammonia using the nitrogenase enzyme.
Metalloenzymes contain metal ions that help catalyze important biochemical reactions. Antioxidants protect cells from oxidative damage caused by free radicals generated during normal metabolism and environmental exposures. There are many classes of antioxidants including vitamins, minerals, enzymes, carotenoids, flavonoids, and phenolic compounds. Antioxidants act as reducing agents that prevent oxidative chain reactions and thereby protect cellular components from oxidative damage.
The document discusses ruthenium-based drugs as potential alternatives to platinum-based anticancer drugs like cisplatin. Ruthenium compounds have properties that make them well-suited for medical applications, including ligand exchange kinetics similar to cisplatin and the ability to exist in multiple oxidation states under physiological conditions. Some ruthenium complexes have shown anticancer activity through interactions with DNA like intercalation and groove binding. The most successful ruthenium-based drug to date is NAMI-A, which can bind DNA but does not appear to cause DNA damage as its mechanism of action.
This document describes research on the heterologous expression of an NADP-dependent [NiFe]-hydrogenase from Pyrococcus furiosus in Escherichia coli. The researchers were able to successfully produce a functional form of the recombinant hydrogenase enzyme by co-expressing 13 P. furiosus genes involved in hydrogenase maturation in E. coli. Remarkably, providing only the four structural genes encoding the hydrogenase subunits and a single protease from P. furiosus was sufficient for the native E. coli maturation machinery to generate functional hydrogenase. This demonstrates that E. coli can assemble a functional hydrogenase from a phylogenetically distant hyperthermophilic organism.
This document contains multiple sections from lectures by Dr. Ashok Kumar J on the topic of cellular respiration and oxidative phosphorylation. It discusses key concepts such as oxidation, reduction, the electron transport chain, ATP synthase, the chemiosmotic theory proposed by Peter Mitchell, and disorders that can result from mitochondrial dysfunction.
Free radicals are highly reactive molecules that are produced through normal cell metabolism and environmental exposures. They can damage cells by reacting with lipids, proteins, and DNA if produced in excess. The body has antioxidant defenses like enzymes and nutrients that neutralize free radicals. However, oxidative stress occurs when there is an imbalance between free radical production and antioxidant defenses, leading to chronic diseases. While free radicals play beneficial roles in small amounts for immune function, too many can contribute to conditions like cancer, cardiovascular disease, neurological disorders, and more.
A free radical is a molecule or molecular fragment that contains one or more unpaired electrons in its outermost orbital.
Free radical is generally represented by superscript dot.
This document summarizes Lionel Graux's research in organometallic chemistry and homogeneous catalysis. His work focuses on synthesizing new ruthenium complexes using secondary phosphine oxides as ligands. He has characterized the complexes and studied their reactivity and catalytic applications. Specifically, he has investigated their use in catalyzing cycloisomerization of arenynes and C-H bond activation reactions. Additionally, he has explored the alpha-addition of 1,3-diketones to ynamides catalyzed by phosphapalladacycles and ruthenium complexes. His other experience includes developing Buchwald-Hartwig coupling methodology and synthesizing iron complexes for olefin polymerization on an industrial scale.
Free radicals are unstable molecules that can damage cells. This document discusses free radicals, how they are produced in the body, and how they damage lipids, proteins, and DNA through oxidation. It also describes biomarkers that are used to measure free radical damage, such as markers of lipid peroxidation (MDA, HNE), protein oxidation (protein carbonyls), and DNA oxidation (8-OHdG). Antioxidants in the body help neutralize free radicals and prevent oxidative damage.
The document describes a new flexible synthesis of pyrazoles that allows for varying substituents at the C3 and C5 positions of the pyrazole ring. The synthesis involves coupling protected alkynols with acid chlorides to form alkynyl ketones, which are reacted with hydrazine to install the pyrazole nucleus. Alcohol deprotection and conversion to chlorides provides access to 5-substituted 3-(chloromethyl)- or 3-(2-chloroethyl)pyrazoles. These chlorides can then undergo nucleophilic substitution to generate other polyfunctional pyrazoles. The significance is that substituents at C5 control the steric environment around the pyrazole N-H
The document describes a thesis submitted by TeQuion Brookins on March 26, 2012 about the influence of the protein cross-linker diethyl acetylenedicarboxylate (DAD) on degradation of proteins by the 20S core particle of the 26S proteasome. The thesis explores how DAD-mediated electrophilic modification can cross-link proteins like the peroxiredoxin Tsa1, inactivate them, and potentially inhibit their degradation by the proteasome. Experiments were conducted to detect increased accumulation of ubiquitin, known proteasomal substrates, and damaged proteins like Tsa1 when yeast cells were treated with DAD, which would indicate disturbance of the cellular protein degradation mechanism. P
Adam B. Powell developed a heterogeneous catalyst composed of palladium, bismuth nitrate, and tellurium metal that promotes the aerobic oxidative esterification of aliphatic alcohols with high yields. The addition of bismuth and tellurium additives significantly increased the rate of product formation and overall yield compared to the catalyst without additives. The catalyst was shown to esterify a variety of activated and aliphatic alcohols, expanding the scope of this transformation. Future work includes adapting the catalyst for other oxidative reactions and developing a robust Pd-Bi-Te catalyst for flow applications.
The document discusses several copper-containing proteins including plastocyanin, copper amine oxidase, hemocyanin, cytochrome c oxidase, tyrosinase, and superoxide dismutase. It describes their structures, catalytic functions, and roles in electron transfer reactions and oxidation processes in photosynthesis, respiration, and melanin production. Deficiencies and disorders related to defects in these copper proteins are also mentioned.
This document discusses reactive oxygen species, reactive nitrogen species, and redox signaling. It covers the following key points:
- Nitric oxide is an important signaling molecule produced through the oxidation of L-arginine by nitric oxide synthase. There are three NOS isoforms.
- Reactive oxygen species include superoxide and hydrogen peroxide. Superoxide is produced by NADPH oxidase and can be converted to hydrogen peroxide. These molecules are involved in cell signaling but can also cause damage.
- Hydrogen sulfide is another gasotransmitter that regulates various physiological processes through protein persulfidation.
- Reactive species can modify protein cysteine residues through oxidation
This document provides an overview of copper complexes used as potential anti-cancer agents. It discusses the role of metal ions in biological systems and copper chemistry. It then describes various analytical techniques used to characterize copper complexes and ligands. Several types of copper complexes are mentioned, including copper(II) complexes of semicarbazones, macrocyclic ligands, and biomolecules. Issues related to toxicity in using metal complexes as drugs are also covered. The conclusion discusses the potential of copper complexes as anticancer drugs due to copper's role in cancer processes and its generally lower toxicity compared to non-essential metals.
A brief introduction about Pharmacology of free radicals, generation of free radicals, Antioxidants, Free radicals causing disorders such as cancer diabetes, neuro degenerative disorders such as Parkisonism's Disease
Oxidative stress occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the body's ability to neutralize them. ROS play a role in many chronic diseases including Alzheimer's disease (AD). The document discusses the sources and reactivity of oxygen free radicals like superoxide, hydrogen peroxide, and hydroxyl radicals that are generated in cells. It also describes how cells protect themselves against oxidants through enzymatic antioxidants like superoxide dismutase, catalase, and glutathione peroxidase. The document then focuses on AD, stating that oxidative stress is thought to play a central role in its pathogenesis by leading to neuronal dysfunction and cell death. Elevated peripheral markers of oxidative stress in AD
The document discusses free radicals and antioxidants. It defines free radicals as unstable chemical species with unpaired electrons that can cause oxidative damage. Free radicals are produced through normal cellular processes but can also be generated by external factors like radiation. They can cause lipid peroxidation, DNA and protein oxidation leading to cell damage associated with aging and diseases. Antioxidants help neutralize free radicals and prevent oxidative stress.
Free radicals are highly unstable chemical species with unpaired electrons that can damage cells. Reactive oxygen and nitrogen species are important free radicals generated through normal cellular processes and environmental exposures that can initiate chain reactions. Free radicals attack and degrade membranes, proteins, and nucleic acids. This can lead to lipid peroxidation, protein oxidation, and DNA damage implicated in various diseases. Cells employ antioxidant defenses and enzymes like catalase and superoxide dismutase to limit free radical damage.
This document discusses reactive oxygen species (ROS), specifically superoxide. It defines ROS as chemically reactive molecules containing oxygen that are produced naturally during cellular metabolism. Superoxide is formed as a byproduct of mitochondrial electron transport and can damage cells when overproduced. The document describes how hydroethidine fluorescence is used to selectively detect superoxide levels in mitochondria, finding increased fluorescence with antimycin stimulation. It concludes that precise superoxide detection aids understanding of its role in signaling and damage.
Particle and Particle Systems Characterization_2013Nidhi Basak
The document discusses the interaction between magnetic iron oxide (Fe3O4) nanoparticles (NPs) and the protein cytochrome c (Cytc). It finds that at low concentrations of bare (uncoated) Fe3O4 NPs, rapid electron transfer from the NPs to Cytc occurs, reducing the protein. However, at higher NP concentrations, a slow oxidative modification of Cytc is initiated by reactive oxygen species generated by the NPs, leading to loss of protein structure and stability. Coating the NPs with polyethylene glycol or dextran inhibits their binding to and effects on Cytc. The interaction between NPs and proteins has implications for both therapeutic applications and toxicity assessments of NPs.
Free radicals are unstable molecules that can damage cells. They are formed through normal metabolic processes but also due to environmental toxins and radiation. The body has antioxidant defenses against free radicals but an excess can lead to oxidative stress and disease. Endogenous free radicals include reactive oxygen species like superoxide, hydrogen peroxide, and hydroxyl radicals produced during metabolism. Exogenous sources include tobacco smoke, drugs, radiation, and air pollution. Free radical damage accumulates with age and is linked to many age-related diseases.
This document describes a new method for selective N-methylation of peptide backbone amides on resin using the Mitsunobu reaction. The key aspects are:
1) N-trifluoroacetamide (Tfa) was used as the protecting group on resin-bound peptides, which can generate a nucleophilic anion for methylation via Mitsunobu conditions.
2) Tfa-protected peptides on resin underwent efficient (80-99%) and selective N-methylation of the backbone amide using the Mitsunobu reaction with triphenylphosphine, methanol and diisopropyl azodicarboxylate.
3) Unlike other reports, the T
The document discusses the electron transport chain (ETC) in mitochondria. It describes the components and organization of the ETC, including the five protein complexes and electron carriers like NADH, FADH2, coenzyme Q, and cytochromes. The ETC transports electrons from donors like NADH to final acceptors like oxygen, pumping protons across the inner mitochondrial membrane. This generates a proton gradient used by ATP synthase to produce ATP through oxidative phosphorylation, with typically 3 ATP produced per NADH oxidized.
The document discusses oxidative phosphorylation, which is the process by which ATP is generated from NADH and FADH2 through electron transport chain located in the mitochondria. It explains that NADH and FADH2 donate electrons that are passed through electron carriers and ultimately reduce oxygen to water, releasing energy. This energy is used to drive ATP synthesis. The document also outlines some diseases associated with defects in oxidative phosphorylation and discusses the role and functions of key proteins involved in the process.
This document describes research on the heterologous expression of an NADP-dependent [NiFe]-hydrogenase from Pyrococcus furiosus in Escherichia coli. The researchers were able to successfully produce a functional form of the recombinant hydrogenase enzyme by co-expressing 13 P. furiosus genes involved in hydrogenase maturation in E. coli. Remarkably, providing only the four structural genes encoding the hydrogenase subunits and a single protease from P. furiosus was sufficient for the native E. coli maturation machinery to generate functional hydrogenase. This demonstrates that E. coli can assemble a functional hydrogenase from a phylogenetically distant hyperthermophilic organism.
This document contains multiple sections from lectures by Dr. Ashok Kumar J on the topic of cellular respiration and oxidative phosphorylation. It discusses key concepts such as oxidation, reduction, the electron transport chain, ATP synthase, the chemiosmotic theory proposed by Peter Mitchell, and disorders that can result from mitochondrial dysfunction.
Free radicals are highly reactive molecules that are produced through normal cell metabolism and environmental exposures. They can damage cells by reacting with lipids, proteins, and DNA if produced in excess. The body has antioxidant defenses like enzymes and nutrients that neutralize free radicals. However, oxidative stress occurs when there is an imbalance between free radical production and antioxidant defenses, leading to chronic diseases. While free radicals play beneficial roles in small amounts for immune function, too many can contribute to conditions like cancer, cardiovascular disease, neurological disorders, and more.
A free radical is a molecule or molecular fragment that contains one or more unpaired electrons in its outermost orbital.
Free radical is generally represented by superscript dot.
This document summarizes Lionel Graux's research in organometallic chemistry and homogeneous catalysis. His work focuses on synthesizing new ruthenium complexes using secondary phosphine oxides as ligands. He has characterized the complexes and studied their reactivity and catalytic applications. Specifically, he has investigated their use in catalyzing cycloisomerization of arenynes and C-H bond activation reactions. Additionally, he has explored the alpha-addition of 1,3-diketones to ynamides catalyzed by phosphapalladacycles and ruthenium complexes. His other experience includes developing Buchwald-Hartwig coupling methodology and synthesizing iron complexes for olefin polymerization on an industrial scale.
Free radicals are unstable molecules that can damage cells. This document discusses free radicals, how they are produced in the body, and how they damage lipids, proteins, and DNA through oxidation. It also describes biomarkers that are used to measure free radical damage, such as markers of lipid peroxidation (MDA, HNE), protein oxidation (protein carbonyls), and DNA oxidation (8-OHdG). Antioxidants in the body help neutralize free radicals and prevent oxidative damage.
The document describes a new flexible synthesis of pyrazoles that allows for varying substituents at the C3 and C5 positions of the pyrazole ring. The synthesis involves coupling protected alkynols with acid chlorides to form alkynyl ketones, which are reacted with hydrazine to install the pyrazole nucleus. Alcohol deprotection and conversion to chlorides provides access to 5-substituted 3-(chloromethyl)- or 3-(2-chloroethyl)pyrazoles. These chlorides can then undergo nucleophilic substitution to generate other polyfunctional pyrazoles. The significance is that substituents at C5 control the steric environment around the pyrazole N-H
The document describes a thesis submitted by TeQuion Brookins on March 26, 2012 about the influence of the protein cross-linker diethyl acetylenedicarboxylate (DAD) on degradation of proteins by the 20S core particle of the 26S proteasome. The thesis explores how DAD-mediated electrophilic modification can cross-link proteins like the peroxiredoxin Tsa1, inactivate them, and potentially inhibit their degradation by the proteasome. Experiments were conducted to detect increased accumulation of ubiquitin, known proteasomal substrates, and damaged proteins like Tsa1 when yeast cells were treated with DAD, which would indicate disturbance of the cellular protein degradation mechanism. P
Adam B. Powell developed a heterogeneous catalyst composed of palladium, bismuth nitrate, and tellurium metal that promotes the aerobic oxidative esterification of aliphatic alcohols with high yields. The addition of bismuth and tellurium additives significantly increased the rate of product formation and overall yield compared to the catalyst without additives. The catalyst was shown to esterify a variety of activated and aliphatic alcohols, expanding the scope of this transformation. Future work includes adapting the catalyst for other oxidative reactions and developing a robust Pd-Bi-Te catalyst for flow applications.
The document discusses several copper-containing proteins including plastocyanin, copper amine oxidase, hemocyanin, cytochrome c oxidase, tyrosinase, and superoxide dismutase. It describes their structures, catalytic functions, and roles in electron transfer reactions and oxidation processes in photosynthesis, respiration, and melanin production. Deficiencies and disorders related to defects in these copper proteins are also mentioned.
This document discusses reactive oxygen species, reactive nitrogen species, and redox signaling. It covers the following key points:
- Nitric oxide is an important signaling molecule produced through the oxidation of L-arginine by nitric oxide synthase. There are three NOS isoforms.
- Reactive oxygen species include superoxide and hydrogen peroxide. Superoxide is produced by NADPH oxidase and can be converted to hydrogen peroxide. These molecules are involved in cell signaling but can also cause damage.
- Hydrogen sulfide is another gasotransmitter that regulates various physiological processes through protein persulfidation.
- Reactive species can modify protein cysteine residues through oxidation
This document provides an overview of copper complexes used as potential anti-cancer agents. It discusses the role of metal ions in biological systems and copper chemistry. It then describes various analytical techniques used to characterize copper complexes and ligands. Several types of copper complexes are mentioned, including copper(II) complexes of semicarbazones, macrocyclic ligands, and biomolecules. Issues related to toxicity in using metal complexes as drugs are also covered. The conclusion discusses the potential of copper complexes as anticancer drugs due to copper's role in cancer processes and its generally lower toxicity compared to non-essential metals.
A brief introduction about Pharmacology of free radicals, generation of free radicals, Antioxidants, Free radicals causing disorders such as cancer diabetes, neuro degenerative disorders such as Parkisonism's Disease
Oxidative stress occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the body's ability to neutralize them. ROS play a role in many chronic diseases including Alzheimer's disease (AD). The document discusses the sources and reactivity of oxygen free radicals like superoxide, hydrogen peroxide, and hydroxyl radicals that are generated in cells. It also describes how cells protect themselves against oxidants through enzymatic antioxidants like superoxide dismutase, catalase, and glutathione peroxidase. The document then focuses on AD, stating that oxidative stress is thought to play a central role in its pathogenesis by leading to neuronal dysfunction and cell death. Elevated peripheral markers of oxidative stress in AD
The document discusses free radicals and antioxidants. It defines free radicals as unstable chemical species with unpaired electrons that can cause oxidative damage. Free radicals are produced through normal cellular processes but can also be generated by external factors like radiation. They can cause lipid peroxidation, DNA and protein oxidation leading to cell damage associated with aging and diseases. Antioxidants help neutralize free radicals and prevent oxidative stress.
Free radicals are highly unstable chemical species with unpaired electrons that can damage cells. Reactive oxygen and nitrogen species are important free radicals generated through normal cellular processes and environmental exposures that can initiate chain reactions. Free radicals attack and degrade membranes, proteins, and nucleic acids. This can lead to lipid peroxidation, protein oxidation, and DNA damage implicated in various diseases. Cells employ antioxidant defenses and enzymes like catalase and superoxide dismutase to limit free radical damage.
This document discusses reactive oxygen species (ROS), specifically superoxide. It defines ROS as chemically reactive molecules containing oxygen that are produced naturally during cellular metabolism. Superoxide is formed as a byproduct of mitochondrial electron transport and can damage cells when overproduced. The document describes how hydroethidine fluorescence is used to selectively detect superoxide levels in mitochondria, finding increased fluorescence with antimycin stimulation. It concludes that precise superoxide detection aids understanding of its role in signaling and damage.
Particle and Particle Systems Characterization_2013Nidhi Basak
The document discusses the interaction between magnetic iron oxide (Fe3O4) nanoparticles (NPs) and the protein cytochrome c (Cytc). It finds that at low concentrations of bare (uncoated) Fe3O4 NPs, rapid electron transfer from the NPs to Cytc occurs, reducing the protein. However, at higher NP concentrations, a slow oxidative modification of Cytc is initiated by reactive oxygen species generated by the NPs, leading to loss of protein structure and stability. Coating the NPs with polyethylene glycol or dextran inhibits their binding to and effects on Cytc. The interaction between NPs and proteins has implications for both therapeutic applications and toxicity assessments of NPs.
Free radicals are unstable molecules that can damage cells. They are formed through normal metabolic processes but also due to environmental toxins and radiation. The body has antioxidant defenses against free radicals but an excess can lead to oxidative stress and disease. Endogenous free radicals include reactive oxygen species like superoxide, hydrogen peroxide, and hydroxyl radicals produced during metabolism. Exogenous sources include tobacco smoke, drugs, radiation, and air pollution. Free radical damage accumulates with age and is linked to many age-related diseases.
This document describes a new method for selective N-methylation of peptide backbone amides on resin using the Mitsunobu reaction. The key aspects are:
1) N-trifluoroacetamide (Tfa) was used as the protecting group on resin-bound peptides, which can generate a nucleophilic anion for methylation via Mitsunobu conditions.
2) Tfa-protected peptides on resin underwent efficient (80-99%) and selective N-methylation of the backbone amide using the Mitsunobu reaction with triphenylphosphine, methanol and diisopropyl azodicarboxylate.
3) Unlike other reports, the T
The document discusses the electron transport chain (ETC) in mitochondria. It describes the components and organization of the ETC, including the five protein complexes and electron carriers like NADH, FADH2, coenzyme Q, and cytochromes. The ETC transports electrons from donors like NADH to final acceptors like oxygen, pumping protons across the inner mitochondrial membrane. This generates a proton gradient used by ATP synthase to produce ATP through oxidative phosphorylation, with typically 3 ATP produced per NADH oxidized.
The document discusses oxidative phosphorylation, which is the process by which ATP is generated from NADH and FADH2 through electron transport chain located in the mitochondria. It explains that NADH and FADH2 donate electrons that are passed through electron carriers and ultimately reduce oxygen to water, releasing energy. This energy is used to drive ATP synthesis. The document also outlines some diseases associated with defects in oxidative phosphorylation and discusses the role and functions of key proteins involved in the process.
ELECTRON TRANSPORT CHAIN AND OXIDATIVE PHOSPHORYLATION.pptRamieMollid
1) The electron transport chain (ETC) transfers electrons from electron carriers NADH and FADH2 through a series of protein complexes in the inner mitochondrial membrane and uses the energy to pump protons across the membrane.
2) The complexes include NADH dehydrogenase (Complex I), succinate dehydrogenase (Complex II), Coenzyme Q - cytochrome c reductase (Complex III), and cytochrome c oxidase (Complex IV). Electron carriers like coenzyme Q and cytochrome c shuttle electrons between complexes.
3) As electrons are passed through the complexes, energy is used to pump protons from the mitochondrial matrix into the intermembrane space, building an electrochemical proton gradient that drives ATP synthesis by
The document discusses the electron transport chain and oxidative phosphorylation. It describes how electrons from nutrients are transferred through enzyme complexes in the mitochondrial membrane to generate a proton gradient. This gradient is then used by ATP synthase to phosphorylate ADP into ATP through oxidative phosphorylation. Inhibitors of the electron transport chain like cyanide and antimycin A prevent this process, while uncouplers allow electron transport without phosphorylation.
The project will focus on synthesis of hexagonal structured pure phases of compositions: BaM1/3Ti2/3O3-δ and BaM1/6Ti5/6O3-δ, where M= Sc, In and Fe via different methods such as Solid state sintering and wet chemical route. The ultimate goal is to finding structure – functionality relationships within these proton and mixed conducting systems. A substantial effort will focus on search for and fabrication of new materials although the main part of the work will concentrate on detailed structural characterisation (rietveld refinement), impedance spectroscopy, infrared spectroscopy and thermogravimetric analysis.
Photosystem I is located in the membrane of cyanobacteria and plants. It contains proteins, chlorophylls, carotenoids, and other cofactors that transfer electrons during photosynthesis. PsaA and PsaB form the core where primary electron transfer occurs. Electrons are transferred from P700 to ferredoxin via a chain containing chlorophyll, phylloquinone, and iron-sulfur clusters. Ferredoxin then transfers electrons to ferredoxin-NADP+ reductase to reduce NADP+ to NADPH, providing energy for the Calvin cycle.
This document summarizes heterogeneous photocatalysis research from the literature. It begins by introducing heterogeneous photocatalysis and its applications. Section II then surveys the types of photocatalytic reactions that have been observed, including oxidations, reductions, isomerizations, substitutions, condensations, and polymerizations. Section III discusses the mechanisms of photocatalysis, involving photoelectrochemistry and the roles of electron-hole pairs, oxygen, hydroxyl radicals, adsorption, and kinetics. Subsequent sections cover topics like active photocatalysts, pretreatment methods, and effects of parameters like pH, temperature, and sensitization.
1. Biological oxidation involves the transfer of electrons between electron donors and electron acceptors. This transfer is facilitated by enzymes called oxidoreductases.
2. The electron transport chain is a series of complexes embedded in the mitochondrial inner membrane that transfers electrons from electron carriers like NADH and FADH2 through a series of redox reactions utilizing carriers like ubiquinone and cytochromes.
3. As electrons are transferred through the complexes of the electron transport chain, protons are pumped from the mitochondrial matrix to the intermembrane space, creating an electrochemical gradient that drives the synthesis of ATP by ATP synthase.
1. Biological oxidation involves the transfer of electrons between electron donors and electron acceptors. This transfer is facilitated by enzymes called oxidoreductases.
2. The electron transport chain is a series of complexes embedded in the mitochondrial inner membrane that transfers electrons from electron carriers like NADH and FADH2 through a series of redox reactions utilizing carriers like ubiquinone and cytochromes.
3. As electrons are transferred through the electron transport chain complexes, protons are pumped from the mitochondrial matrix to the intermembrane space, creating an electrochemical gradient that drives the synthesis of ATP by ATP synthase utilizing oxidative phosphorylation.
reactive oxygen species in periodontal diseaseSuhani Goel
This document summarizes the role of reactive oxygen species (ROS) and antioxidants in periodontal tissue destruction. It defines key terms like free radicals, oxidative stress, and antioxidants. It describes the major ROS molecules like superoxide, hydrogen peroxide, and hydroxyl radicals. These molecules are produced endogenously through metabolic pathways and phagocytosis, and can cause tissue damage by oxidizing lipids, proteins, and DNA. This oxidative damage disrupts cellular functions and structures. The document also discusses how ROS induce transcription factors and cytokine release to promote inflammation. Maintaining the pro-oxidant/antioxidant balance is important for periodontal health.
(1) Free radicals are highly reactive molecules with unpaired electrons that can cause oxidative damage. They are produced through normal metabolic processes and from environmental sources. (2) Antioxidants protect against free radical damage by neutralizing free radicals through enzymatic and non-enzymatic mechanisms. Key antioxidant enzymes include superoxide dismutase and catalase. Vitamins C and E are important non-enzymatic antioxidants. (3) Oxidative stress occurs when there is an imbalance between free radicals and antioxidants in favor of free radicals, potentially leading to cell and tissue damage associated with various diseases if left unchecked.
Oxidative phosphorylation and photophosphorylation are the two main mechanisms by which organisms generate ATP. In oxidative phosphorylation, electrons are passed through an electron transport chain in mitochondria to reduce oxygen to water, pumping protons across the inner mitochondrial membrane. The resulting proton gradient is used by ATP synthase to phosphorylate ADP to ATP. Photophosphorylation uses sunlight to drive electron transport and proton pumping across thylakoid membranes in chloroplasts to similarly synthesize ATP. Both mechanisms conserve the energy of electron transport as a proton gradient that is then used to power ATP synthesis, demonstrating the fundamental similarity between these critical energy conversion processes.
Chapter 7 Energy transduction in cells.pptxAsmamawTesfaw1
Cellular respiration includes both aerobic and anaerobic respiration. Aerobic respiration fully oxidizes glucose or other fuels and generates the most ATP. It involves glycolysis, the citric acid cycle, and the electron transport chain which uses oxygen as the final electron acceptor. During these processes, energy released is used to synthesize ATP through substrate-level phosphorylation and oxidative phosphorylation. Anaerobic respiration utilizes other molecules besides oxygen as electron acceptors, and fermentation generates only a small amount of ATP without using the electron transport chain.
Electron Transport and Oxidative PhosphorylationHamid Ur-Rahman
The document summarizes electron transport and oxidative phosphorylation in mitochondria. It describes how:
1) The electron transport chain in the inner mitochondrial membrane is made up of four complexes that transfer electrons from nutrients to oxygen, pumping protons from the matrix to the intermembrane space.
2) As electrons are passed through the complexes, energy is used to transport protons against their concentration gradient, building up a electrochemical proton gradient across the inner membrane.
3) ATP synthase uses the potential energy in this proton gradient to phosphorylate ADP, producing ATP through oxidative phosphorylation.
Andrew Fielding's doctoral research focused on understanding the mechanism of O2 activation and catalysis by two similar catechol dioxygenases: Fe(II)-homoprotocatechuate 2,3-dioxygenase (Fe-HPCD) and Mn(II)-MndD. He prepared and characterized the cobalt-substituted variant of HPCD, which showed higher activity than Mn- or Fe-HPCD despite Co(II) being a poorer reducing agent. Using electron-poor substrate analogs, he was able to trap and characterize three O2 intermediates by EPR, providing new insights into dioxygenase mechanisms. Comparing the properties of different metal-substituted enzymes allowed full characterization
Biological oxidation and Electron Transport Chain is the most important and confusing topic in biochemistry metabolism, but here we tried to put it in the simplest way easy to learn. This presentation was guided by Dr. Arpita Patel and made by Miss Nidhi Argade.
A single amino acid mutation (E95Q) in the NuoF subunit of respiratory Complex I from Escherichia coli results in a 15-fold increase in the rate of reactive oxygen species (ROS) production. The mutant's flavin mononucleotide (FMN) is reduced faster by an anionic reductant. Titration of the ROS production rate as a function of redox potential shows a positive shift that fits a Nernst plot with n=2, indicating a two-electron process. Measurements using variants with impaired quinone reductase activity show similar ROS production rates and redox potentials as the wild type, arguing against a significant role for quinones or the N2 channel
FREE RADICAL CELL INJURY PPT BY Dr. Tareni Das.pdfTARENIDAS
Free radicals are unstable chemical species with unpaired electrons that are highly reactive. They are produced through normal metabolic processes and environmental exposures. The document defines different types of reactive oxygen species and reactive nitrogen species, which include both radicals and non-radicals. Sources of free radical production are discussed, as well as their positive and negative biological effects through lipid peroxidation, protein and DNA oxidation. Methods for assessing free radical activity and oxidative stress are outlined.
The document describes the electron transport chain in mitochondria. It has three key points:
1. The electron transport chain consists of four complexes embedded in the inner mitochondrial membrane, along with electron carriers like CoQ, cytochromes, and Fe-S centers that shuttle electrons between the complexes. Complexes I, III, and IV establish a proton gradient by pumping protons out of the matrix.
2. Electrons enter the chain from NADH and FADH2, and are passed through the carriers and complexes until they reach oxygen and are used to form water. This electron transfer is coupled to proton pumping.
3. The proton gradient drives ATP synthase to phosphorylate ADP into ATP,