briefly describe enzyme and coenzyme and its role in many orders. Consist of enzyme nomenclature, enzyme part: prosthetic group, metalions, cofactors, and secondary substrate. Describe inhibition action.
Enzymalogy Factors affecting enzyme activity and kineticsrohini sane
A comprehensive presentation on Factors affecting enzyme activity & Kinetics of Enzymes for MBBS ,BDS, B Pharm & Biotechnology students to facilitate self- study.
An enzyme is a substance that acts as a catalyst in living organisms, regulating the rate at which chemical reactions proceed without itself being altered in the process. The biological processes that occur within all living organisms are chemical reactions, and most are regulated by enzymes
Enzymalogy Factors affecting enzyme activity and kineticsrohini sane
A comprehensive presentation on Factors affecting enzyme activity & Kinetics of Enzymes for MBBS ,BDS, B Pharm & Biotechnology students to facilitate self- study.
An enzyme is a substance that acts as a catalyst in living organisms, regulating the rate at which chemical reactions proceed without itself being altered in the process. The biological processes that occur within all living organisms are chemical reactions, and most are regulated by enzymes
A comprehensive presentation on Enzymology :Types of Enzyme inhibition & Therapeutic uses for MBBS ,BDS, B Pharm & Biotechnology students to facilitate self- study.
The flux of metabolites through metabolic pathways involves
catalysis by numerous enzymes. Active control of homeostasis is achieved by the regulation of only a small number of enzymes.
A comprehensive coverage of Enzymes including basics, mechanisms of enzyme catalysis, enzyme inhibition and clinical applications, mostly based on Stryer- Biochemistry. The slides were intended for MBBS teaching, but should benefit the students of Biochemistry and allied sciences.
Prepared in Sept 2015
Introduction, Nomenclature of enzymes, Classification of enzymes on the basis of site of action, on the reaction of catalysis and Classification depends upon substrates on they which act, Specificity of Enzymes, Active Site of An Enzyme: 1. Lock-key model 2. Induce fit model, Factors Affecting Enzymes Reaction, Enzyme 1.Inhibition Competitive inhibition, 2. Non-Competitive inhibition, Isoenzymes, Allosteric Enzymes, Co-Factors, Turnover Number of An Enzyme, Pharmaceutical Importance Of Enzymes,
A comprehensive presentation on Enzymology :Types of Enzyme inhibition & Therapeutic uses for MBBS ,BDS, B Pharm & Biotechnology students to facilitate self- study.
The flux of metabolites through metabolic pathways involves
catalysis by numerous enzymes. Active control of homeostasis is achieved by the regulation of only a small number of enzymes.
A comprehensive coverage of Enzymes including basics, mechanisms of enzyme catalysis, enzyme inhibition and clinical applications, mostly based on Stryer- Biochemistry. The slides were intended for MBBS teaching, but should benefit the students of Biochemistry and allied sciences.
Prepared in Sept 2015
Introduction, Nomenclature of enzymes, Classification of enzymes on the basis of site of action, on the reaction of catalysis and Classification depends upon substrates on they which act, Specificity of Enzymes, Active Site of An Enzyme: 1. Lock-key model 2. Induce fit model, Factors Affecting Enzymes Reaction, Enzyme 1.Inhibition Competitive inhibition, 2. Non-Competitive inhibition, Isoenzymes, Allosteric Enzymes, Co-Factors, Turnover Number of An Enzyme, Pharmaceutical Importance Of Enzymes,
What are Enzymes; Properties of enzymes; Classification of Enzyme; Mechanism of action of enzyme; Enzyme-Substrate Interactions; Enzyme Activation; Enzyme Inhibition; What are Coenzymes; Salient features of coenzyme; Some Co-Enzymes & its function.
An enzyme is a biological catalyst and is almost always a protein. It speeds up the rate of a specific chemical reaction in the cell. The enzyme is not destroyed during the reaction and is used over and over.
This presentation includes:
1.1 : Introduction
1.2 : Classification and nomenclature of enzymes
1.3 : Structure and properties of enzymes
1.4: Mechanism of enzymes action-
Lock and Key hypothesis and Induced fit hypothesis.
1.5: factors affecting enzyme activity- temperature and pH.
1.6: Enzyme inhibition.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
4. What will we learn?
• Foreword
• Nomenclature
• Activation
• Inhibition and mechanism of inhibition
• Factor that affect enzymes activity
5. Foreword
• Enzyme are proteins (or RNA) with powerful
catalytic activity thus called biocatalysator
• Synthesized by biological cells and in all organism,
they are involved in chemical reactions related to
metabolism
• Alcoholic, ripening, aging of meat, etc.
• Enzymes play a role in food science
6. Catalysis
• Catalyst is substance that increase reaction
without consumed by the reaction
• Feature of catalyst
– Lowers the activation energy needed to start a
reaction
– Is not used up during the reaction
– Is unchanged after a reaction
10. Nomenclature
• Enzyme classified based on type and
mechanism of reaction
• Old time: based on hydrolysis of covalent
bond
– Protease, lipase, amylase, etc.
• In one substrate can occur other reaction, not
only hydrolysis
• Now: enzyme classified based on type and
mechanism of reaction
11. IUB nomenclature system
• International Union of Biochemistry
1. Reaksi dan enzim yang mengatalisis enzim tersebut
membentuk enam kelas, masing-masing mempunyai
4-13 sub kelas
2. Nama enzim terdiri atas dua bagian, nama pertama
menunjukkan substrat dan nama kedua yang berakhiran
ase menyatakan tipe reaksi yang dikatalisis
3. Informasi tambahan, bila diperlukan untuk menjelaskan
reaksi dapat dituliskan dalam tanda kurung di bagian
akhir
4. Enzim memiliki EC yang mencirikan tipe reaksi ke dalam
reaksi (digit pertama), subkelas (digit kedua),
subsubkelas (digit keempat)
12. Based on EC
1. EC 1 Oksidoreduktase: mengatalisis reaksi
oksidasi/reduksi
2. EC 2 Transferase: mentransfer gugus fungsi
3. EC 3 Hidrolase: mengatalisis hidrolisis berbagai
ikatan
4. EC 4 Liase: memutuskan berbagai ikatan kimia selain
melalui hidrolisis dan oksidasi
5. EC 5 Isomerase: mengatalisis isomerisasi sebuah
molekul tunggal
6. EC 6 Ligase: menggabungkan dua molekul dengan
ikatan kovalen
15. Enzyme cofactors
• Rigorous analysis has demonstrated that
numerous enzymes are not pure proteins
• They can contain metal ions and/or low
molecular weight nonprotein organic
molecules
• These nonprotein hetero constituents are
denoted as cofactor which are indispensable
for enzyme activity
16. Systematics of cofactor-containing enzymes
Holo-enzyme
Cofactor Apoenzyme
Metalions Coenzyme
Proeshetic group Cosubstrate
Stable binding Cyclic regeneration
Involved in reaction
17.
18. Metalions
• Metalions commonly called cofactor
• Function:
– Stabilizers of enzyme conformation
– Direct participation in catalysis
• Located in active site
• Common metal ions:
– Magnesium, calcium and zinc
– Iron, Copper, and molybdenum
22. Flavin
• Riboflavin known as Vit. B2 is the building
block of flavin mononucleotide (FMN) and
Flavin adenine dinuleotide (FAD)
• Both act as prostetic groups for electron
transfer reactions in number of enzymes
23.
24. Hemin
• Peroxidases from food of plant origin and
several catalases contain ferri-protoporphyrin
IX
• Chromophore responsible for the brown color
of the enzymes
• In catalytic reactions there is a change in the
electron excitation spectra of the peroxidases
26. Pyridoxal phosphate
• Pyridoxal phosphate are designated as
vitamin B6 and are essential ingredients of
food
• Coupled to the enzyme as a prosthetic group
through a lysyl residue, involved in
conversion reactions of amino acids
28. Role of Vitamin as prosthetic group
www.chemistryexplained.com
29. Cosubstrate
• Consist of NAD and ATP
• Nicotinamide adenine dinucleotide (NAD+)
– Transhydrogenase (e.g. lactate dehydrogenase,
alcohol dehydrogenase) dehydrogenate or
hydrogenate their substrates with the help of
pyridine cosubstrates
– NAD residue accepts or donate a hydride ion (H-)
30.
31. Theory of Enzyme Catalysis
• Active site
– Small part of enzyme where reaction of catalysis
occurs
– Enzyme molecule is often larger in size by a
factor of several orders of magnitude
– Prove: Glucose oxydase (Mr= 150,000) which
glucose (Mr=180)
32. Substrate binding
• Stereospecificity
– Before being bound to the binding locus, the
substrates are distinguished by their cis-, trans-
isomerism and by their optical antipodes
• Lock and key hypothesis
– E. Fisher
• Induced-fit model
– The active site can ‘move’ to get correct position
before catalysis reaction occurs
34. Temperature
• Remind that enzyme is consist of protein?
• Denaturation
• But every enzyme has it own characteristic,
regarding to its sulfide bond (or cystein bond):
– Low amount of sulfide bond sensitive to higher
temperature
• Trypsin denaturated in 95oC
– High amount of sulfide bondTaq Polymerase
still active in 95oC
35.
36. pH
• pH affect 3D conformation of enzyme
• Different enzyme different optimum pH