the solanaceae plants produce a variety of interesting biologically active products including the steroid alkaloids solanidine, nicotine and tropane alkaloids. putrescine n-methyltransferase (pmt) is an enzyme that catalyses s-adenosylmethionine-dependent methylation of putrescine in one of the primary steps of nicotine and tropane alkaloids biosynthesis pathway. two tobacco members of the ap2/...