Precursor

Name:
Precursor
Detailed information:
In biochemistry, an intermediate compound or molecular complex present in a living organism; when activated physiochemically it is converted to a specific functional substance. The prefix pro- is usually used to indicate that the compound in question is a precursor. Examples are ergosterol (pro−vitamin D₂), which is activated by UV radiation to vitamin D; carotene(pro−vitamin A), a precursor of vitamin A; prothrombin, which forms thrombin upon activation in the bloodclotting mechanism; and phenylacetic acid, a precursor in the biosynthesis of penicillin G.