Question

Experiment II: Effect of Substrate Concentration on the Rate of Enzyme Reaction

What does this influence indicate about the enzyme function?

Answer 1

When the amount of enzyme is kept constant and substrate concentration is gradually increased, the rate of reaction increases to a certain point after which it will remain constant, I.e. Rate of reaction will not increase with substrate concentration after this point.

A graph of rate of reaction Vs substrate concentration shows an increase in the rate of reaction with increase in substrate concentration till a point after which a plateau is seen because all the enzymes are saturated, as all the enzymes molecules are bound by the substrates. More substrate added has to wait till a catalytic site becomes empty to bind to and undergo reaction. Thus the rate of reaction will not increase further. The rate of reaction when enzyme is saturated with substrate is the maximum rate of reaction and is called Vmax.