putrescine biosynthesis amine and polyamine biosynthesis putrescine biosynthesis via agmatine pathway Agmatine, which results from the decarboxylation of L-arginine by arginine decarboxylase, is a metabolic intermediate in the biosynthesis of putrescine and higher polyamines (spermidine and spermine). Recent studies indicate that agmatine can have several important biochemical effects in humans, ranging from effects on the central nervous system to cell proliferation in cancer and viral replication. PMID:11673419 PMID:12435743 pathway MetaCyc:PWY-43 UPa:UPA00534 GO:0033388 MetaCyc:PWY-40 PMID:11804860 KEGG:map00330 PMID:12634339 KEGG:map01100