Spermine is a polyamine involved in

cellular metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run c ...

that is found in all eukaryotic cells. The precursor for synthesis of spermine is the amino acid

ornithine Ornithine is a non-proteinogenic amino acid that plays a role in the urea cycle. Ornithine is abnormally accumulated in the body in ornithine transcarbamylase deficiency. The radical is ornithyl. Role in urea cycle L-Ornithine is one of the produ ...

. It is an essential

growth factor A growth factor is a naturally occurring substance capable of stimulating cell proliferation, wound healing, and occasionally cellular differentiation. Usually it is a secreted protein or a steroid hormone. Growth factors are important for regul ...

in some

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

as well. It is found as a polycation at physiological pH. Spermine is associated with nucleic acids and is thought to stabilize helical structure, particularly in

virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsk ...

es. Antonie van Leeuwenhoek first described crystals of spermine phosphate in human semen in 1678. The name ''spermin'' was first used by the German chemists

Ladenburg Ladenburg is a town in northwestern Baden-Württemberg, Germany. It lies on the right bank of the river Neckar, northwest of Heidelberg and east of Mannheim. The town's history goes back to the Celtic and Roman Ages, when it was called Lopo ...

and Abel in 1888, and the correct structure of spermine was not finally established until 1926, simultaneously in England (by Dudley, Rosenheim, and Starling) and Germany (by Wrede et al.). Spermine is the chemical primarily responsible for the characteristic odor of semen.

Derivative

derivative In mathematics, the derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value). Derivatives are a fundamental tool of calculus. ...

of spermine, N¹, N¹²-bis(ethyl)spermine (also known as BESm) was investigated in the late 1980s along with similar polyamine analogues for its potential as a cancer therapy.

Biosynthesis

Spermine biosynthesis in animals starts with decarboxylation of

by the enzyme

Ornithine decarboxylase The enzyme ornithine decarboxylase (, ODC) catalyzes the decarboxylation of ornithine (a product of the urea cycle) to form putrescine. This reaction is the committed step in polyamine synthesis. In humans, this protein has 461 amino acids a ...

in the presence of PLP. This decarboxylation gives putrescine. Thereafter the

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

spermidine synthase effects two

N-alkylation In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent such ...

by decarboxy- S-Adenosyl methionine. The intermediate is

spermidine Spermidine is a polyamine compound () found in ribosomes and living tissues and having various metabolic functions within organisms. It was originally isolated from semen. Function Spermidine is an aliphatic polyamine. Spermidine synthase (SP ...

. Plants employ additional routes to spermine. In one pathway L-glutamine is the precursor to L-ornithine, after which the synthesis of spermine from L-ornithine follows the same pathway as in animals. Polyamine synthesis

Another pathway in plants starts with decarboxylation of L-arginine to produce

agmatine Agmatine, also known as 4-aminobutyl-guanidine, is an aminoguanidine that was discovered in 1910 by Albrecht Kossel. Agmatine is a chemical substance which is naturally created from the amino acid arginine. Agmatine has been shown to exert modula ...

. The imine functional group in agmatine then is hydrolysed by agmatine deiminase, releasing

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

, converting the

guanidine Guanidine is the compound with the formula HNC(NH2)2. It is a colourless solid that dissolves in polar solvents. It is a strong base that is used in the production of plastics and explosives. It is found in urine predominantly in patients experie ...

group into a urea. The resulting N-carbamoylputrescine is acted on by a

hydrolase Hydrolase is a class of enzyme that commonly perform as biochemical catalysts that use water to break a chemical bond, which typically results in dividing a larger molecule into smaller molecules. Some common examples of hydrolase enzymes are este ...

to split off the urea group, leaving putrescine. After that the putrescine follows the same pathway to completing the synthesis of spermine.

Derivative

Biosynthesis

References

Further reading