The biosynthesis of plant alkaloids and nitrogenous microbial metabolites

The biosynthesis of plant alkaloids and nitrogenous microbial metabolites

“…The labelling of C-2, C-5, C-7, and C-12 by [I-13C]acetate established that biosynthesis of (28) was likely to be by a polyketide route.31 The acetate units were then firmly located by the results of an experiment with [l3C,]acetate and the remaining atoms could be defined as arising from propionate by the results of an experiment with [l-13C]propionate (Scheme 2). Important confirmation that all three carbon atoms of the cyclopropyl residue originate in propionate was obtained with [3,3,3 In well-detailed work it has been shown that there is a key biosynthetic enzyme, called (5')-norlaudanosoline s y n t h a ~e ~~,…”

“…The course of biosynthesis of quinolizidine alkaloids has been probed further with deuteriated samples of cadaverine. [3,]Cadaverine (19) has been incorporated into (+)lupanine ( 21) and (+)-13a-hydroxylupanine (22) in Lupinus polyphyllus2B and Lupinus a n g ~s t i f o l i u s , ~~ into ( + )-angustifoline (23) in L. polyphyllus, and into (-)-lupinhe ( 24) and (-)sparteine (20) in Lupinus luteus. *' The labelling patterns illustrated on structures (20>- (24) were determined by *H n.m.r.…”

The biosynthesis of plant alkaloids and nitrogenous microbial metabolites

“…The enzyme involved is called caffeoyl-CoA putrescine N-caffeoyl transferase. l 3 1.1 Pyrrolidine Alkaloids Al-N-Methylpyrrolinium Salt (1) is a precursor for cocaine (2) in Erythroxylum coca with label at C-2 in the former appearing at C-5 in the alkaloid. The CoA ester of (3) has been identified as a possible biosynthetic intermediate14 (cf.…”

The biosynthesis of plant alkaloids and nitrogenous microbial metabolites

“…Like the latter metabolite, tuberin has been shown to derive from t y r o ~i n e ~~ (cf: ref. 3, p. 173). Racemic threo-phydroxytyrosine ( 63) was shown to act as a precursor for tuberin (62) in Streptomyces amakusaensis but only after it had been degraded.…”