This refers to the turnover number (a.k.a kcat or k2) of an
enzyme and is usually calculated using Michaelis-Menten
kinetics. Jump to the summary at the end if you want a simple
answer. If you want a more thorough answer, consider the
following chemical equation: This says that a certain
concentration of enzyme mixed with a certain concentration of
substrate will first combine and form a complex depending on the
enzyme's affinity for the substrate. Then the enzyme complex
will generate a product depending on the enzyme's ability to
convert the transition state into product. The k1 constant is
the arrow moving from [E] + [S] → [ES] and the k-1 is the arrow
moving from [ES] → [E] + [S] (they oppose each other). The k2
constant is the arrow moving from [ES] → [E] + [P]. This can
also be expressed in terms of maximum rate: So k2 is basically
an indicator of how efficiently or quickly an enzyme operates.
Not all enzymes follow standard Michaelis-Menten kinetics. For
example, the allosteric properties of some enzym