Describe several mechanisms by which enzymes lower activation energy?

1. Proximity effects. Enzymes bind to their substrates; and if both of those substrates are hanging out together attached to the enzyme somehow, they're more likely to interact. Imagine if you had two friends, who didn't know each other at all. If you act as the enzyme, and bring them into proximity by inviting them to the same party at your house, they're that much more likely to start talking and become friends themselves - their new friendship is the formation of the product in the reaction.

2. Breaking of covalent bonds. Sometimes, when the enzyme binds to the substrate, this binding disrupts existing bonds between the residues of the substrate. When it was there, that bond might have blocked other molecules from interacting with the substrate. Now that it's removed, it allows the substrate to react and form the product. Imagine again that you are the enzyme, and the substrate is one of your friends (a very stupid friend, I suppose) who would like to hold hands with his girlfriend. Unfortunately, your friend is holding onto his own ears with both hands. You grab one of his wrists, and pull his hand away from his head; now his girlfriend is able to take his hand. Them holding hands is the finished product of the reaction.

3. Conformational stress. Sometimes when the enzyme binds to the substrate, it pulls the substrate molecule into an "uncomfortable" position. The substrate can't stay in that position for very long, so it quickly reacts to "escape" from the stress the enzyme has put on it. The strain the enzyme puts on the substrate can also be enough to break existing bonds and create new bonds. Imagine the enzyme is a chiropractor, bending its substrate almost in half until a knot gives way (bond breaking) and a nicely aligned spine results (product formation).

Enzymes bind briefly to a minimum of various of of the reactants of the reaction they catalyze. In doing so, they decrease the quantity of activation ability mandatory and to that end velocity up the reaction. Eg: Catalase. It catalyzes the decomposition of hydrogen peroxide into water and oxygen. 2H2O2 -> 2H2O + O2 One molecule of catalase can destroy 40 million molecules of hydrogen peroxide each and each 2d. by utilising offering an determination reaction path and by utilising stabilizing intermediates the enzyme reduces the flexibility required to be triumphant in the optimal ability transition state of the reaction. E+S(SUBSTRATE)---------->E-S(complicated)-... enzymes decrease the flexibility by utilising performing on a definite substrate forming E-S complicated WHICH enter the reaction and advance up it by utilising elevating the substance floor state to the transitional state (advance the loose ability of the substrate mandatory to offer the product so the flexibility mandatory to start the reaction will decrease ). Enzymes are no longer ate up in the process the reaction.