a substance (as a coenzyme) that must join with another to produce a given result
cofactor详细解释
co.fac.tor n.（名词）A substance, such as a metallic iron or coenzyme, that must be associated with an enzyme for the enzyme to function.辅助因素：必须与酶联合以使酶起作用的一种物质，例如金属铁或辅酶
