Regulatory Strategies II: Zymogen activation, Digestive Proteases; Fibrinogen and Prothrombin; Reversible Covalent Modification: (Phosphorylation with special reference to Glycogen phosphorylase)
Regulatory Strategies II: Proteolytic activation (Zymogen activation)(Digestive Proteases; Fibrinogen; Prothrombin); Reversible Covalent Modification (Phosphorylation with special reference of Glycogen phosphorylase
The catalytic activity of the proteins is regulated in four principal ways:
- Allosteric control
- Multiple forms of enzymes (Isoenzymes)
- Proteolytic activation (Zymogen activation)
- Reversible covalent modification
Zymogens and their activation
- Many enzymes are activated by the hydrolysis of a few or even one peptide bond in inactive precursors called zymogens or proenzymes.
- Zymogen activation do not require ATP hydrolysis.
- Important mode of regulation for both extracellular and intracellular enzyme
- The activation of zymogen is an irreversible reaction.
- The digestive enzymes that hydrolyze proteins are synthesized as zymogens in the stomach and pancreas
- Blood clotting is mediated by a cascade of proteolytic activations that ensures a rapid and amplified response to trauma.