2 - Enzymes, Coenzymes, and Bacterial Growth Kinetics

Abstract

This chapter provides an overview of enzymes, coenzymes, and bacterial growth kinetics. Enzymes are true catalysts because they do not influence the point of equilibrium of the reaction they catalyze, nor are they used up during catalysis. Like other catalysts, enzymes lower the activation energy of the reaction they catalyze to obtain an equilibrium state of the reaction. It is impossible for the catalysis to overshoot this equilibrium state. Every enzymatically catalyzed reaction keeps on reacting until the equilibrium state is obtained. Enzymes consist of a protein component and a prosthetic group. Enzymes are not only chemically specific; they are also sterically specific when they act on substances containing asymmetric centers. The substrate may contain an asymmetric carbon atom, in which case it is usually found that the enzyme acts on only one of the optical isomers. To function, many enzymes require certain organic substances as cofactors. The cofactors, or coenzymes, generally act as acceptors or donors of groups of atoms that are removed from or contributed to the substrate. The most striking feature of these coenzymes is that the majority is either actual nucleotides or has some structural analogy with nucleotides.