INTRODUCTION
DEFINITION
STRUCTURE
TYPES OF BONDS
N-LINKED GLYCOSYLATION
O-LINKED GLYCOSYLATION
AMOUNT OF CARBOHYDRATES PRESENT IN GLYCOPROTEIN
BIOLOGICAL SIGNIFICANCE AND
FUNCTION
BIOLOGICAL ADVANTAGE OF ADDING OLIGOSACCHARIDES TO PROTEIN
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle.
More than half of all proteins interact with membranes.
Protein targeting or protein sorting is the biological mechanism by which proteins are transported to their appropriate destinations in the cell or outside it. Proteins can be targeted to the inner space of an organelle, different intracellular membranes, plasma membrane, or to exterior of the cell via secretion.
I have tried to make a precise presentation on protein transport, targeting and sorting into organelle's other than nucleus. Hope this might help you. Comments are welcome.
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle.
More than half of all proteins interact with membranes.
Protein targeting or protein sorting is the biological mechanism by which proteins are transported to their appropriate destinations in the cell or outside it. Proteins can be targeted to the inner space of an organelle, different intracellular membranes, plasma membrane, or to exterior of the cell via secretion.
I have tried to make a precise presentation on protein transport, targeting and sorting into organelle's other than nucleus. Hope this might help you. Comments are welcome.
Protein targeting or protein sorting is the mechanism by which a cell transports to the appropriate positions in the cell or outside of it. Both in prokaryotes and eukaryotes, newly synthesized proteins must be delivered to a specific sub-cellular location or exported from the cell for correct activity. This phenomenon is called protein targeting. Protein targeting is necessary for proteins that are destined to work outside the cytoplasm.This delivery process is carried out based on information contained in the protein itself. Correct sorting is crucial for the cell; errors can lead to diseases. In 1970, Günter Blobel conducted experiments on the translocation of proteins across membranes. He was awarded the 1999 Nobel Prize for his findings. He discovered that many proteins have a signal sequence, that is, a short amino acid sequence at one end that functions like a postal code for the target organelle.
Introduction-Cell wall and functions
Gram +ve and -ve cell wall
Bacterial cell wall - structure
Peptidoglycan-Composition and Structure
Types of polysaccharidesBacterial cell wall
Functions of polysaccharides in Bacterial cell wall
Reverse transcription of RNA, which refers to the conversion of the RNA template into its complimentary DNA strand (cDNA) is an essential step in the analysis of gene transcripts.
cDNA can be sequenced, cloned and applied to estimate the copy number of specific genes in order to characterize and to validate gene expression.
Introduction
History
Experiment of Ramachandran
Structure of protein
Primary structure
Secondary structure
Tertiary structure
Quaternary structure
Peptide bond is rigid & planar
Torsion angle (Φ and Ψ)
Ramachandran plot
For helices
For β strands
Significance of Ramachandran plot
Conclusion
Reference
BIOSYNTHESIS OF PHOSPHOLIPIDS
Phospholipids:-
These are compounds containing, in addition to fatty acid and glycerol, phosphoric acid, nitrogenous bases, and another substituent. Polar compounds composed of alcohol attached by phosphodiester bridge to either diacylglycerol or sphingosine.
Amphipathic in nature has a hydrophilic head (phosphate +alcohol
eg., serine, ethanolamine, and choline) and a long, hydrophobic tail
(fatty acids or derivatives ).
- CLASSIFICATION OF PHOSPHOLIPIDS:-
- Glycerophospholipids
- Spingophospholipids or Sphingomyelin
- SYNTHESIS OF PHOSPHOLIPIDS
- FUNCTIONS OF PHOSPHOLIPIDS
- FUNCTIONS OF SPHINGOLIPIDS
This file include these contents:
What is Triacylglycerol
Structure of triacylglycerol
Simple triacylglycerol
Mixed triacylglycerol
Biosynthesis of triacylglycerol
Utilization of triacylglycerol
Properties of triacylglycerol
Protein Folding-biophysical and cellular aspects, protein denaturationAnishaMukherjee5
Protein folding is the physical process by which a protein chain acquires its native 3-dimensional structure, a conformation that is usually biologically functional, in an expeditious and reproducible manner.
Glycoprotein, lipoprotein, by kk sahu sirKAUSHAL SAHU
INTRODUCTION
STRUCTURE
TYPES OF BONDS
N-LINKED GLYCOSYLATION
O-LINKED GLYCOSYLATION
AMOUNT OF CARBOHYDRATES PRESENT IN GLYCOPROTEIN
BIOLOGICAL SIGNIFICANCE AND
FUNCTION
BIOLOGICAL ADVANTAGE OF ADDING OLIGOSACCHARIDES TO PROTEIN
Protein targeting or protein sorting is the mechanism by which a cell transports to the appropriate positions in the cell or outside of it. Both in prokaryotes and eukaryotes, newly synthesized proteins must be delivered to a specific sub-cellular location or exported from the cell for correct activity. This phenomenon is called protein targeting. Protein targeting is necessary for proteins that are destined to work outside the cytoplasm.This delivery process is carried out based on information contained in the protein itself. Correct sorting is crucial for the cell; errors can lead to diseases. In 1970, Günter Blobel conducted experiments on the translocation of proteins across membranes. He was awarded the 1999 Nobel Prize for his findings. He discovered that many proteins have a signal sequence, that is, a short amino acid sequence at one end that functions like a postal code for the target organelle.
Introduction-Cell wall and functions
Gram +ve and -ve cell wall
Bacterial cell wall - structure
Peptidoglycan-Composition and Structure
Types of polysaccharidesBacterial cell wall
Functions of polysaccharides in Bacterial cell wall
Reverse transcription of RNA, which refers to the conversion of the RNA template into its complimentary DNA strand (cDNA) is an essential step in the analysis of gene transcripts.
cDNA can be sequenced, cloned and applied to estimate the copy number of specific genes in order to characterize and to validate gene expression.
Introduction
History
Experiment of Ramachandran
Structure of protein
Primary structure
Secondary structure
Tertiary structure
Quaternary structure
Peptide bond is rigid & planar
Torsion angle (Φ and Ψ)
Ramachandran plot
For helices
For β strands
Significance of Ramachandran plot
Conclusion
Reference
BIOSYNTHESIS OF PHOSPHOLIPIDS
Phospholipids:-
These are compounds containing, in addition to fatty acid and glycerol, phosphoric acid, nitrogenous bases, and another substituent. Polar compounds composed of alcohol attached by phosphodiester bridge to either diacylglycerol or sphingosine.
Amphipathic in nature has a hydrophilic head (phosphate +alcohol
eg., serine, ethanolamine, and choline) and a long, hydrophobic tail
(fatty acids or derivatives ).
- CLASSIFICATION OF PHOSPHOLIPIDS:-
- Glycerophospholipids
- Spingophospholipids or Sphingomyelin
- SYNTHESIS OF PHOSPHOLIPIDS
- FUNCTIONS OF PHOSPHOLIPIDS
- FUNCTIONS OF SPHINGOLIPIDS
This file include these contents:
What is Triacylglycerol
Structure of triacylglycerol
Simple triacylglycerol
Mixed triacylglycerol
Biosynthesis of triacylglycerol
Utilization of triacylglycerol
Properties of triacylglycerol
Protein Folding-biophysical and cellular aspects, protein denaturationAnishaMukherjee5
Protein folding is the physical process by which a protein chain acquires its native 3-dimensional structure, a conformation that is usually biologically functional, in an expeditious and reproducible manner.
Glycoprotein, lipoprotein, by kk sahu sirKAUSHAL SAHU
INTRODUCTION
STRUCTURE
TYPES OF BONDS
N-LINKED GLYCOSYLATION
O-LINKED GLYCOSYLATION
AMOUNT OF CARBOHYDRATES PRESENT IN GLYCOPROTEIN
BIOLOGICAL SIGNIFICANCE AND
FUNCTION
BIOLOGICAL ADVANTAGE OF ADDING OLIGOSACCHARIDES TO PROTEIN
Lipoprotein introduction, their general characteristics, exogenous and endogenous metabolism focusing on chylomicron and vldl metabolism, ldl metabolism and HDL metabolism , reverse cholesterol transport.
Introduction
General structure of lipoprotein
Apo lipoprotein
Classification of lipoprotein
Chylomicron
LDL- low density lipoprotein
HDL- high density lipoprotein
VLDL- very low density lipoprotein
IDL- intermediate density lipoprotein
Clinical disorders
Preventive measures
Lipoprotein analysis
Diet , cholesterol and lipoprotein
Lipids are hydrophobic molecules (They are afraid of water).
● They are transported in the plasma as lipoprotein structures.
● Lipoproteins are spherical (كروي (macromolecular complexes¹ of :
○ Lipids²
○ Specific protein ( Apolipoproteins )
● Lipoproteins keep lipid contents soluble while transporting them
to and from the tissues.
Types of lipoproteins : ● Chylomicrons (lowest density, largest) ● Very low density lipoproteins ( VLDL ) ● Low density lipoproteins ( LDL ) ● H
Lipoproteins differ in : ● Density (means weight) ● Size (The most density molecule is the smallest in size) ● Site of origin ● Composition of lipids and proteins
Introduction
History
Tumor suppressor gene- pRB
- RB gene
- Role of RB in regulation of cell cycle
- Tumor associated with RB gene mutation
Tumor suppressor gene- p53
- What is p53 gene?
- Function of p53 gene
- How it regulates cell cycle
- What happen if p53 gene inactivated
- Cancer associated with p53 mutation
- Conclusion
- References
Introduction
Definition
History
Two hit hypothesis
Functions
Mutation in tumor suppressor genes
What is mutation
Inherited mutation of TSGs
Acquired mutation of TSGs
What is Oncogenes?
TSGs and Oncogenes : Brakes and accelerators
Stop and go signal
Examples of TSGs:
RB-The retinoblastoma gene
P53 protein
TSGs &cell suicide
Conclusion
References
Introduction
Protein synthesis
Synthesis of secretory proteins on membrane-bound ribosomes
Processing of newly synthesized proteins in the ER
Synthesis of integral membrane protein on membrane bound ribosomes
Maintenance of membrane asymmetry
Conclusion
Reference
Introduction
Definition
Factors required for Translation
Formation of aminoacyl t-RNA
1)Activation of amino acid
2) Transfer of amino acid to t-RNA
Translation involves following steps:-
1)Initiation
2)Elongation
3)Termination
Conclusion
Reference
Introduction
Definition
History
central dogma
Major components
mRNA,tRNA,rRNA
Energy source
Amino acids
Protien factor
Enzymes
Inorganic ions
Step involves in translation:
Aminoacylation of tRNA
Initiation
Elongation
termination
Importance of translation
Conclusion
Reference
Introduction
Protein modifications
Folding
Chaperon mediated
Enzymatic
Cleavage
Addition of functional groups
Chemical groups
Hydrophobic groups
Proteolysis
Conclusion
Reference
INTRODUCTION
HISTORY
WHAT IS TRANSCRIPTION
PROKARYOTIC TRANSCRIPTION
STEPS OF TRANSCRIPTION
HOW TRANSCRIPTION OCCURS
PROCESS OF TRANSCRIPTION
Initiation
Elongation
Termination
CONCLUSION
REFRENCES
Enzyme Kinetics and thermodynamic analysisKAUSHAL SAHU
Introduction
Kinetics and thermodynamicSG
Thermodynamic in enzymatic reactions
balanced equations in chemical reactions
changes in free energy determine the direction & equilibrium state of chemical reactions
the rates of reactions
Factors effecting enzymatic activity
(i) Enzyme concentration.
(ii) Substrate concentration.
(iii)Temperature
(iv) pH.
(v) Activators.
(vi)Inhibitors
Michaelis-menten equation
CONCLUSIONS
REFERENECES
Recepter mediated endocytosis by kk ashuKAUSHAL SAHU
INTRODUCTION
DEFINITION OF RECEPTOR MEDIATED ENDOCYTOSIS
WHAT TYPE OF LIGANDS ENTER BY RME?
FORMATION OF CLATHRIN-COATED VESICLES
TRISKELIONS
ROLE OF DYNAMIN IN THE FORMATION OF CLATHRIN-COATED VESICLES
ROLE OF PHOSPHOLIPIDS IN THE FORMATION OF COATED VESICLES
ENDOCYTIC PATHWAY
LDLs AND CHOLESTROL METABOLISM
CONCLUSION
REFERENCES
The delivery of newly synthesized protein to their proper cellular destination, usually referred to as protein targeting or sorting.
The mode of protein transport depends chiefly on the location in the cell cytoplasm of the polysomes involved in protein synthesis.
There are two modes of protein sorting:-
1) Co - translational Transportation.
2) Post - translational Transportation.
Prokaryotic translation machinery by kk KAUSHAL SAHU
Introduction
Definition
Factors required for Translation
Formation of aminoacyl t-RNA
1)Activation of amino acid
2) Transfer of amino acid to t-RNA
Translation involves following steps:-
1)Initiation
2)Elongation
3)Termination
Conclusion
Reference
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Richard's aventures in two entangled wonderlandsRichard 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.
BREEDING METHODS FOR DISEASE RESISTANCE.pptxRASHMI M G
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Lateral Ventricles.pdf very easy good diagrams comprehensive
Glycoprotein, lipoprotein, structure and function
1. Glyco- & lipo- proteins structure & function
1
By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )
2. SYNOPSIS for Glycoproteins
• INTRODUCTION
• DEFINITION
• STRUCTURE
• TYPES OF BONDS
• N-LINKED GLYCOSYLATION
• O-LINKED GLYCOSYLATION
• AMOUNT OF CARBOHYDRATES PRESENT IN GLYCOPROTEIN
• BIOLOGICAL SIGNIFICANCE AND
• FUNCTION
• BIOLOGICAL ADVANTAGE OF ADDING OLIGOSACCHARIDES TO PROTEIN
3. INTRODUCTION
Glycoprotein have been defined as conjugated proteins
which contains one or more saccharides lacking a serial repeat
unit and are bound covalently to a protein.
Glycoproteins are resultant from the covalent attachment
of carbohydrate chains both linear and branched in structure to
various sites on the polypeptide backbone of a protein.
Glycoproteins are conjugated proteins which are
biologically active molecules. In Glycoprotein the prosthetic part
is carbohydrate.
5. STRUCTURE
• Covalent linkage of a sugar to the proteins is a central part of
Glycoprotein structure.
• Among the several different classes of conjugated proteins
Glycoprotein's are one of them which represent a large group
of conjugated proteins with their biological significance.
• Carbohydrates are linked to proteins by N or O – linkage or N
– or O – glycosyl bonds.
1. N - Glycosyl linkage to asparagine.
2. O – Glycosyl linkage to serine.
6.
7. N-linked glycosylation is important for the folding of some
eukaryotic proteins.
•The N-linked glycosylation process occurs in eukaryotes and
widely in archaea, but very rarely in bacteria.
• For N-linked oligosaccharides, a 14-sugar precursor is first
added to the asparagines in the polypeptide chain of the target
protein.
•The structure of this precursor is common to most eukaryotes,
and contains 3 glucose, 9 mannose, and 2 N-acetylglucosamine
molecules.
N-linked Glycosylation
8. O-linked glycosylation occurs at a later stage during protein
processing, probably in the Golgi apparatus.
• This is the addition of N-acetyl-galactosamine to serine or threonine
residues by the enzyme UDP-N-acetyl-D- galactosamine:polypeptide N-
acetyl galactosaminyl transferase followed by other carbohydrates (such
as galactose and sialic acid).
• This process is important for certain types of proteins such as
proteoglycans, which involves the addition of glycosaminoglycan chains
to an initially unglycosylated "proteoglycan core protein."
O-linked Glycosylation
10. Amount of carbohydrates in glycoprotein
Glycoprotein Amount of
carbohydrate
1. IgG
2. Glycophorin
3. Human ovarian cyst
4. Human gastric
glycoprotein
5. FSH
6. LH
7. TSH
8. Chorionic gonadotropin
4%
60%
70%
82%
18.2%
15.7%
16.2%
31%
11. BIOLOGICAL SIGNIFICANCE
• Glycoproteins in cell membranes may have an important role in the behavior
of cell and especially in the biological function of the membrane.
• Glycoproteins are constituents of the mucus secreted by certain epithelial
cells, where they mediate lubrication and protection of tissues lining the
respiratory, gastrointestinal and female reproductive system.
• Many secreted protiens are glycoproteins and they also includes
a) Hormones :- FSH, LH, TSH, chorionic gonadotropin.
b) Plasma proteins:- Orosomucoids, ceruloplasmin, plasminogen,
prothrombin and immunoglobulins.
12. FUTNCION
• The role of carbohydrates in glycoprotein structure/function
seems to involve their role in directing proper folding of proteins
in the ER .
•In cell membrane they help to stabilise the membrane structure
as they forms hydrogen bonds with water molecules in the fluid
surrounding the cell.
•The most important function of glycoprotein in animal cell is to
increase the strength and impermeability of the outer bilipid
layer.
•Defence against infection:- IgG, interferon.
13. Synopsis for Lipoproteins
• INTRODUCTION
• DEFINITION
• TYPES OF LIPOPROTEINS
• COMPOSITION OF LIPOOPROTEIN
• TRANSPORT OF LIPOPROTEIN INSIDE THE CELL
• TRANSPORT OF LIPOPROTEIN IN HUMAN BODY
• BIOLOGICAL ADVANTAGE OF ADDING LIPIDS TO PROTEIN /
FUNCTIONS OF LIPOPROTEINS
• CONCLUSION
• REFERENCES
14. • What are lipoproteins and why do we need them?
– Lipoproteins are a handful of different molecules that interact
with water insoluble fat molecules, and transports those fats in
the plasma.
– Different lipoproteins are responsible for the transportation of
different fats.
– Lipoproteins allow fat to be dissolved into the plasma.
– Function: Transport of fat soluble substances
14
16. • There are 4 types of lipoproteins
– Chylomicrons
• Transport of dietary triglycerides from the GI tract to the liver
– Very Low Density Lipoproteins ( VLDL )
• Transport of triglycerides from the liver to tissues for storage and
energy
– Low Density Lipoproteins ( LDL )
• Transports cholesterol to peripheral tissues
– High Density Lipoproteins ( HDL )
• Transports cholesterol away from the peripheral tissues to the liver
16
17. • Lipid Chemistry
– Lipids include
• Cholesterol
• Triglycerides
• Phospholipids
• Glycolipids
– Lipids are important components of cell membranes
17
18. – Fatty acids are short to long carbon chained molecules
• Saturated fatty acids
– No double bonds between carbons ( C – C )
– Solid at room temperature
– Animal sources
• Unsaturated fatty acids
– Double bonds between carbon bonds ( C = C)
– Usually liquid at room temp
– Plant sources
18
19. • Triglycerides
– Glycerol with 3 attached fatty acids.
– 95 % of body fat is triglycerides.
– Energy source when plasma glucose is decreased.
– Triglycerides transported by Chylomicrons (exogeneous) and VLDL
(endogenous).
19
20. • Cholesterol
– Found only in animals.
– Important component of membranes, steroid hormones, bile and
Vitamin D.
– Exogeneous cholesterol comes from diet.
– Endogeneous cholesterol is synthesized by the liver.
– 70 % of cholesterol associated with cellular components.
– 30 % is in the plasma ( ⅓ free form , ⅔ esterfied )
– Transported by HDL and LDL
20
21. • Apolipoproteins
– Outer protein “shell” of the lipoprotein molecule.
– The protein – lipid interaction allows the water insoluble lipid to
become soluble in plasma.
– The apolipoprotein is responsible for the interactions with cell
membranes and enzymes to transport lipids to specific locations.
21
22. • Lipoproteins
– Classified according to density and electrophoresis migration.
– Lipoproteins differ in their sizes, weights, chemical composition,
etc.
– There are four main types of lipoproteins
• CHYLOMICRONS
• VLDL
• LDL
• HDL
22
23. • Chylomicrons
– Transports exogeneous ( dietary ) triglycerides.
– 90 - 95 % by weight is triglycerides.
– Absent from fasting plasma.
– Inadequate clearance produces a creamy layer on the plasma.
• VLDL ( Very Low Density Lipoproteins )
– Transports endogenous triglycerides from liver to tissues.
– 50 - 65 % by weight is triglycerides.
– Excess dietary carbohydrates are converted to triglycerides by the liver.
– Once VLDL looses much of its TG’s it becomes LDL
23
24. • LDL ( Low Density Lipoproteins )
– Transports cholesterol from liver to the tissues.
– Synthesized in the liver.
– Approximately 50 % by weight cholesterol.
– Most atherogenic lipoprotein … “ Bad Cholesterol“.
• HDL ( High Density Lipoprotein )
– Transports excess cholesterol from the tissues back to the liver (
reverse transport ).
– Synthesized in the liver and intestines.
– Composition:
• 30% PHOSPHOLIPIDS
• 20% CHOLESTEROL
• 50% APOPROTEIN
– The “good “ cholesterol. 24
25. Lipoprotein
class
Density
(g/mL)
Diameter
(nm)
Protein %
of dry wt
Phosphol
ipid %
Triacylglycerol
% of dry wt
HDL 1.063-1.21 5 – 15 33 29 8
LDL 1.019 –
1.063
18 – 28 25 21 4
IDL 1.006-1.019 25 - 50 18 22 31
VLDL 0.95 – 1.006 30 - 80 10 18 50
chylomicrons < 0.95 100 - 500 1 - 2 7 84
Composition and properties of human
lipoproteins
27. •After the clathrin coat
disassembles, the vesicle fuses
with an endosome.
•LDL is released from the
receptor within the acidic
environment of the endosome,
and the receptor is returned to
the plasma membrane.
•After LDL is transferred to a
lysosome, cholesterol is
released & may be used, e.g., for
• Cells take up LDL by receptor-
mediated endocytosis, involving
formation of a clathrin-coated pit
& pinching off of a vesicle
incorporating the receptor & LDL
cargo.
LDL
extracellular space
LDL
receptor
receptor-mediated
endocytosis
cytosol
Receptor Mediated Endocytosis -
28.
29. •The lipoprotein allows fats to move through the water inside and outside cells
•Lipoprotein carry cholestrol & similar substance through the blood.
•The handling of lipoprotein particles in the body is reffered to as lipoprotein
particle metabolism.
FUNCTION
30. CONCLUSION
Glycoprotein are important glycoconjugates. They are covalently attach
to carbohydrates. They are found on the outer face of the plasma
membrane, in the extra cellular matrix and in the blood.
Glycoprotein has various biological advantages and their study is very
important in AIDS,INFLUENZA and other diseases.
Lipoproteins are also important lipoconjugates, which are helpful in the
transportation of Lipid molecules in the inside the human body.
31. REFERENCE
1. TEXT BOOK OF BIOCHEMISTRY
LEHNINGER NELSON & COX (iv EDITION)
2. TEXT BOOK OF BIOCHEMISTRY
WILSON & WALKER