Turnover Number

The turnover number of an enzyme, k cat, gives a direct measure of the catalytic production of product under optimum conditions (saturated enzyme). The units of k cat are seconds-1. The reciprocal of k cat can be thought of as the time required by an enzyme molecule to "turn over" one substrate molecule. Alternatively, k cat measures the number of substrate molecules turned over per enzyme molecule per second. Thus, k cat is sometimes called the turnover number. Some typical turnover numbers are shown in Table 11.1, as well.

See also: Michaelis-Menten Kinetics, Analysis of Kinetic Data, K M, k CAT, and k CAT/K M

INTERNET LINK: Enzyme Kinetics