BIOL 112 Lecture Notes - Lecture 10: Conformational Change, Competitive Inhibition, Metabolic Pathway

• School: McGill University
• Department: Biology
• Course: BIOL 112
• Professor: Frieder Schoeck

Document Summary

Catalyst is substance that speed up chemical reaction without being used up itself. Most biological catalysts are enzyme proteins, some are 3d-folded rnas. Only reactions will - g can be catalyzes, overall g is unchanged! Critical as many reactions do not proceed spontaneously at 37 c , activation e cannot be overcome. Substrate binds to enzyme forming enzyme-substrate complex , enzyme makes conformational change to bring reactant to transition state. When products leave enzyme it resumes its shape and can be recycled. Substrates are bound in specific orientation , exposed to altered charge environments or have strain induced on covalent bonds to facilitate catalysis. Cofactors : small organic molecules or ions (not aas) that catalyze reaction. Can consist of temporarily bound or permanently bound molecules (ex. Saturation : when all binding sites occupied. Further increase of substrate [ ] will not increase rate of product formation. Nearly always down-regulated by final product to avoid overproduction ( end-product inhibition )