Proteolysis 1

Proteolysis 1

1. proteolysis

2. Table of content: What is meant by proteolysis? How protein degradation occur? Where protein degradation occur? Why we need proteolysis?

3. INTRODUCTION The term proteolysis mean “breakdown or lysis of protein or primary substance.” Proteolysis is the breakdown of proteins or peptides into amino acids.

4. How proteins breakdown occur? The hydrolytic breakdown of proteins into substances such as peptides and simpler, soluble amino acids, by the action of enzymes which are named as “proteolytic enzymes” or “proteases”

5. proteases Proteases are of two types: EXOPEPTIDASES ENDOPEPTIDASES OR PROTEINASES

6. EXOPEPTIDASE They cleave near the N or C terminus of peptides or proteins. Example: carboxypeptidase Aminopeptidase

7. E ndopeptidases They cleave internal peptide bonds in peptides and proteins. Example: pepsin,renin,trypsin,chymotrypsin.

8. Where protein degradation occur? It occurs in several compartments: Lysosomal protein breakdown(individual protease degrade proteins) Ubiquitin-dependent protein breakdown(proteosome system degrades proteins)

9. Lysosomal protein breakdown Acidic pH Various hydrolyses ( proteases,nucleases) Significance: Degradation of extracellular or intracellular fragments. PROTEIN UPTAKE: Endocytosis Autophagy phagocytosis

10. Ubiquitin-dependent protein breakdown Neutral Ph ATP-dependent degradation Significance: Digestion of proteins programmed for quick destruction Digestion of misfolding Denatured Abnormal proteins

11. Why we need proteolysis? The most utmost function of proteolysis is in regulation of proteins. It activate a cellular protein or switch it off by impairing its functionality. Proteolysis is implicated in Digestion Cell cycle regulation apoptosis

12. Proteolysis is a common means of activating enzymes and other proteins in biological systems. For example: the digestive enzymes that hydrolyze proteins are synthesized as zymogens in the stomach and pancreas. the common activator of all the pancreatic zymogen is trypsin. to activate the proenzyme enteropeptidase hydrolyze lysine-isoleucine peptide bond.

13. Example: Fibrinogen is made up of three globular chains. fibrinogen is converted by thrombin into fibrin clot and hydrolyze 4 arginine-glycine peptide bond.

14. THANK YOU