BCH210H1 Lecture Notes - Lecture 20: Methylene Group, Competitive Inhibition, Chymotrypsinogen

• School: UTSG
• Department: Biochemistry
• Course: BCH210H1
• Professor: Stavroula Andreopoulos, Roman Melnyk, Sian Patterson, Reinhart Reithmeier

Document Summary

Zymogen inactive precursor that is activated when needed (enzyme) Chymotrypsinogen secreted by the pancreas and activated in the small intestine, producing chymotrypsin. Disulfide bonds hold the overall structure (the a, b and c chains) together. Irreversible covalently modify a side chain; only way to reactivate would be cleavage of the molecule or synthesis of new enzyme. Competitive inhibitor binds to the active site. Uncompetitive inhibitor can only bind to the es complex. Noncompetitive inhibitor binds to the enzyme or es complex (binds distally, whether the substrate is bound or not) Eg. cyclooxygenase (prostaglandin h2 synthase) irreversible. Signalling molecule associated with inflammation and pain. Important serine (has a hydroxyl side chain); this has the ability to react with aspirin; acetyl group is transferred to the serine molecule, blocking the active site and preventing arachidonic acid from binding. The inhibited enzyme will be turned over this is why aspirin"s effects wear off over time.