Canadian Medical Guide > Chemicals and Drugs > Enzymes and Coenzymes Terms and Definitions

Enzymes and Coenzymes

	Coenzymes - Small molecules that are required for the catalytic function of ENZYMES. Many VITAMINS are coenzymes.
	Cytochromes - Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.
	Enzyme Precursors - Physiologically inactive substances that can be converted to active enzymes.
	Enzymes - Biological molecules that possess catalytic activity. They may occur naturally or be synthetically created. Enzymes are usually proteins, however catalytic RNA (RNA, CATALYTIC) and catalytic DNA (DNA, CATALYTIC) molecules have also been identified.

Enzymes and Coenzymes Medical Definitions and Terms