Enzyme Catalysis

Enzyme Catalysis

Reactions that have a negative net free energy change may occur in the cell.
1. Those that have a positive or zero free energy cannot occur
Enzymes do not affect the equilibrium position of a reaction
1. Chains are folded to form pockets or clefts that constitute where the reaction occurs
2. several weak bonds are needed.
Nature
1. First stage
  1. substrate is converted to a transition state
  2. readily converted into a product in second stage
2. Reaction can occur if there is a decrease in free energy in going from starting material to product
3. Energy profile involves passing over an "energy hump" where the transition state is at higher free energy than the starting materials.
  1. energy is required to reach the transition state
  3. reaction rate is determined by the rate of formation of the transition state
antibodies produced against the transition state. They are called "abzymes"
interaction between the substrate and enzyme so that the enzyme changes shape slightly.
1. this is known as the "induced fit" mechanism.
2. hexokinase consists of two wings that fold around glucose as it binds to the enzyme

Resource summary

	Created by kathrynmoar over 10 years ago