Cofactors

Part of speech: noun

Definitions

1. A substance that assists in biochemical reactions, often serving as a necessary component or coenzyme in enzyme activity
2. An additional element that enhances or is required for the efficacy of biological catalysts
3. Referring to various non-protein molecules or ions that are essential for the catalytic function of enzymes in metabolic processes

Etymology: Before "factor" named anything in chemistry, it meant a person who acted on someone else's behalf: a commercial agent, a steward, or a go-between who handled goods and money. It comes from Latin "factor", "doer or maker", from the verb "facere", "to do or make". That root also gave English "fact", "feat" and "manufacture". The prefix "co-" comes from Latin "com-", "together", so a cofactor is literally a co-doer, a partner that works alongside the main agent. In biochemistry, an enzyme often cannot complete its chemical work alone. Metal ions such as zinc or iron, and organic molecules such as certain vitamins, step in as partners, which matches the older commercial sense of a joint agent closely. The mathematical sense of "factor", a quantity that multiplies with another to produce a product, comes from the same Latin root.