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secondary metabolite

Friday 22 May 2009

Secondary metabolites are organic compounds that are not directly involved in the normal growth, development or reproduction of organisms.

Unlike primary metabolites, absence of secondary metabolities results not in immediate death, but in long-term impairment of the organism’s survivability/fecundity or aesthetics, or perhaps in no significant change at all.

Secondary metabolites are often restricted to a narrow set of species within a phylogenetic group.


The function or importance of these compounds to the organism is usually of an ecological nature as they are used as defenses against predators, parasites and diseases, for interspecies competition, and to facilitate the reproductive processes (coloring agents, attractive smells, etc).

Since these compounds are usually restricted to a much more limited group of organisms, they have long been of prime importance in taxonomic research.

Secondary metabolites may be likely candidates for drug or other technological development directly, or as an inspiration for unnatural products.

This will concern secondary metabolites in plants, bacteria, fungi and many marine organisms (sponges, tunicates, corals, snails).

In some cases, higher organisms will host a microorganism which is the actual producer of the product in question, as part of a symbiotic relationship.


Most of the secondary metabolites of interest to humankind fit into categories which classify secondary metabolites based on their biosynthetic origin.

Since secondary metabolites are often created by modified primary metabolite synthases, or "borrow" substrates of primary metabolite origin, these categories should not be interpreted as saying that all molecules in the category are secondary metabolites (for example the steroid category), but rather that there are secondary metabolites in these categories.

Biosynthesis of secondary metabolites

- terpenoid biosynthesis
- diterpenoid biosynthesis
- monoterpenoid biosynthesis
- limonene and pinene degradation
- indole and ipecac alkaloid biosynthesis
- zeatin biosynthesis
- carotenoid biosynthesis
- brassinosteroid biosynthesis
- phenylpropanoid biosynthesis
- flavonoid biosynthesis
- flavone and flavonol biosynthesis
- anthocyanin biosynthesis
- isoflavonoid biosynthesis
- alkaloid biosynthesis I
- alkaloid biosynthesis II
- acridone alkaloid biosynthesis
- caffeine metabolism
- benzoxazinone biosynthesis
- penicillin and cephalosporin biosynthesis
- beta-Lactam resistance
- streptomycin biosynthesis
- tetracycline biosynthesis
- clavulanic acid biosynthesis
- puromycin biosynthesis
- novobiocin biosynthesis
- insect hormone biosynthesis

See also

- metabolisms