Polyamine like putrescine is derived from:

Ans. (b) Ornithine* Polyamines like spermine, spermidine and putrescine metabolite are produced from L-ornithine by action of ODC (ornithine decarboxylase).* S-Adenosylmethionine, the methyl group donor for many biosynthetic processes, also participates directly in spermine and spermidine biosynthesis.