The benefit of measuring the initial rate of a reaction (V0) is that at the beginning of a reaction: Changes in [S] are negligible, so [S] can be treated as a constant [ES] can be measured accurately Varying [S] has no effect on V0 The activation energy of a reaction cannot be lowered Why does the V0 versus [S] plot eventually plateau? The active site of the enzyme is saturated with substrate The substrate is being consumed The enzymes affinity for the substrate changes The enzyme is being degraded by proteases The benefit of measuring the initial rate of a reaction (V0) is that at the beginning of a reaction: Changes in [S] are negligible, so [S] can be treated as a constant [ES] can be measured accurately Varying [S] has no effect on V0 The activation energy of a reaction cannot be lowered Why does the V0 versus [S] plot eventually plateau? The active site of the enzyme is saturated with substrate The substrate is being consumed The enzymes affinity for the substrate changes The enzyme is being degraded by proteases