The biosynthesis of plant alkaloids and nitrogenous microbial metabolites

Biogenetic speculation and biosynthetic advances

“…Developments in the biosynthesis of alkaloids formed by oxidative coupling have been regularly updated by Herbert in Natural Product Reports. [189][190][191] There still remains some doubt as to the degree of involvement of radical versus ionic mechanisms in oxidative coupling. These uncertainties may be resolvable by the application of modern genetic and enzymatic probes, including for example, 'snapshot' X-ray techniques which, as noted earlier, have been utilised by Baldwin and colleagues to investigate the mechanism of oxidation of the tripeptide precursor of penicillins by isopenicillin N synthase.…”

The biosynthesis of plant alkaloids and nitrogenous microbial metabolitesThis review and those that preceded it are dedicated to my three teachers who were each a marvellous scientific inspiration: F. G. Holliman, A. R. Battersby and G. Stork. They were the giants onto whose shoulders I was privileged to climb.

“…73 The results 74 of experiments with 15 N-and 13 C-labelled precursors in Chromobacterium violaceum demonstrate, in the biosynthesis of violacein 38 from two molecules of tryptophan (ref. 5, p. 364), that the 5-hydroxyindole moiety is the product of an intramolecular rearrangement (1, 2-shift of the indole fragment in tryptophan) and that, in the oxindole moiety, the ring carbon remains attached to the β-carbon of the original tryptophan side chain; appropriate incorporation of [2-13 C, α-15 N]-tryptophan showed that the "central" nitrogen atom is associated with the tryptophan that provides the oxindole moiety. Overall then, the right-hand part of 38 derives simply from tryptophan, with decarboxylation.…”

The biosynthesis of plant alkaloids and nitrogenous microbial metabolites (1997 to 1998)

“…The labelling in scopolamine 18 and hyoscyamine (ref. 6, p. 359) was of both C-2 and C-4 (as well as C-3) indicating curiously that both the (R)-and (S)-isomers acted as precursors.…”

“…Subsequent to hydroxylation, the synthase catalyses the cyclisation of 134 to afford clavaminic acid 128 (ref. 6,p. 367,Scheme 12).…”

“…As previously, reference is made to background material in earlier reports in this series as well as to a monograph. [1][2][3][4][5][6][7][8] As full coverage of the literature as possible was obtained, in part, by use of CAS Online. Jasmonic acid 1 has been identified as an important compound in the elicitation of the biosynthesis of secondary metabolites in higher plants.…”