Polyamines, spennine, spermidine and putrescinc, small aliphatic nitrous bases, are normal constituents of microbial, plant and animal cells, where they fulfill an array of physiological roles. Metabolism of polyamines is associated with growth and differentiation of mammalian cells, spermine related to RNA and spermidine to DNA metabolism. Methyl-cobalamin, the coenzyme of methionine synthetase, catalyses the recycling of homocysteine to methionine using 5-methyltctrahydrofolate. By acceleration of methionine biosynthesis these vitamins may influence spermidine and spermine synthesis.
