Activities of Enzymes

Tham Seng Choe sengchoe at pobox.org.sg
Tue Aug 19 00:28:51 EST 1997


Hi there,

I have some queries regarding the workings of an enzyme.

We understand from most books that the enzyme speeds up a reaction BUT does
not change the equilibrium of the reaction. Assuming a general equation ...

S + Enzyme(E) ---> ES-complex ---> E + P

An enzyme speeds up the formation of a product by providing an alternative
pathway with lower activation energy so that the forward reaction proceeds
with a faster rate. However, this does not show how the corressponding
backward reaction rate is adjusted (increased in this case) to keep the
equilibrium of the entire reaction unchanged.

Does the enzyme catalyse the backward reaction as well? If so, would this
not compromise on the "specificity" of the enzyme? And would this not
provide a form a competitive inhibition which would decrease the efficiency
of the enzyme?

So, how is the increase in the rate of the forward reaction balanced to
maintain the equilibrium?




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