Describe how enzymes speed up chemical reactions (both energetically and physically!), and how they affect the energy and equilibrium of a reaction. Describe 6 different physical and chemical factors that can regulate enzyme activity.

Enzymes are unconsumed during a reaction and do not alter the position of chemical equilibrium. O True O False

Many enzyme mechanisms involve transferring protons. Sidechains of an enzyme can act as catalytic acids or catalytic bases in this process. The figure below shows a step in the reaction by the enzyme triose phosphate isomerase. Glu165 group. -OH Would a catalytic acid gain or lose a proton? Which sidechain in the mechanism is acting as a catalytic acid? co CH,OPO, 2- Activity remaining (%) Would a catalytic base gain or lose a proton? Which sidechain in the mechanism is acting as a catalytic base? 100 Curve I 8 Glu¹65 9 Below are two pH rate profiles showing the percent activity as a function of pH. Answer the questions below about how these curves relate to the mechanism of triose phosphate isomerase. Remember what fraction of a titratable group is unprotonated at the pka. 10 OH In this reaction a carbonyl is converted into an enol intermediate. Circle the enol 100 Activity remaining (%) H Curve 2 CIOH CIOH CH₂OPO,²- 8 9 N N 10 7 pH PH i) Which of these curves shows the pH rate…

Consider the reaction coordinate diagram shown below. X is is Catalysts lower the amount of energy required to reach the transition state (the activation energy) Energy Ground state of reactant Reaction coordinate AG of catalyzed reaction AG of the reaction Ground state of product ; Y