@ low temps near/below 0^oC, enzyme activity low. enzyme inactivated, minimal KE for collision w/ substrate to form E-S complexes

as temp. increase before optimum temp, rate of reaction increases. increase in heat increases KE of substrate & enzyme, increases molecular motion. freq. of successful collisions b/w substrate, enzyme increases; rate of formation of E-S complexes increases -> rate of formation of products increase

@ optimum temp, max rate of reaction. highest frequency of successful collisions b/w substrate & enzyme.

as temp. increases beyond optimum temp, rate of reaction decreases. heat disrupts H bonds, hydrophobic interactions in 2^o, 3^o structures -> specific 3D conformation of AS lost -> enzyme denatured. substrate can no longer bind to AS of enzyme to form E-S complexes, decreasing rate of formation of E-S complexes -> rate of formation of products decreases.

Review: H2 Biology 5 - Enzymes