Zusammenfassung der Ressource
Enzyme Catalysis
- Reactions that have a negative net free
energy change may occur in the cell.
- Those that have a positive or
zero free energy cannot
occur
- Enzymes do not affect the equilibrium
position of a reaction
- Chains are folded to form pockets or clefts
that constitute where the reaction occurs
- several weak bonds are needed.
- Nature
- First stage
- substrate is converted
to a transition state
- readily converted into a
product in second stage
- Reaction can occur if there is a decrease in free
energy in going from starting material to product
- Energy profile involves passing over an "energy hump" where
the transition state is at higher free energy than the starting
materials.
- energy is required to reach the transition state
- 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.
- this is known as the "induced fit" mechanism.
- hexokinase consists of two wings that fold
around glucose as it binds to the enzyme