BIOC 2580 Chapter Notes - Chapter 8: Non-Competitive Inhibition, Competitive Inhibition, Chymotrypsin

• School: University of Guelph
• Department: Biochemistry
• Course: BIOC 2580
• Professor: Enoka Wijekoon

Document Summary

Synopsis: inhibitors control enzyme activity by reversibly decreasing the enzyme activity. Different mechanisms of inhibition depend on the relationship between inhibitor and substrate, and can be distinguished by observing how inhibitor affects km or vmax of the enzyme. Competitive inhibition increases km with no effect on vmax. Non-competitive inhibition decreases vmax with no effect on km. Various substances can act on enzymes to reduce their activity. Inactivation results from a reactive molecule that may form covalent bonds with key amino acids, preventing the enzyme from completing its reaction cycle. Essentially, an inactivator reduces the quantity of available enzyme irreversibly and in a stoichiometric manner: 3 mol enzyme + 2 mol inactivator leaves 1 mol enzyme to continue working. e. g. disopropylfluorophosphate irreversibly, blocking transmission of nerve impulses. Many so-called nerve gases act this way and many are halogen- phosphorus compounds. reacts with acetylcholinesterase. Reversible inhibition results from a substance that binds to an enzyme and limits its capacity to catalyze reaction.