The biosynthesis of plant alkaloids and nitrogenous microbial metabolites

Abstract

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Some Aspects of Guanidine Secondary Metabolites

“…On the other hand, [l-13 C]acetate is efficiently incorporated in the biosynthesis ofracemomycin A (26) (102). HERBERT (111) Scheme 1. It has also been demonstrated that the D-gulosamine moiety of streptothricin F (9, n = 1) and racemomycin A (26) arises from D-glucosamine (108,112,113).…”

“…Moreover, it was observed that labeled (24) and its enantiomer serine is efficiently incorporated into the serine residue of capreomycin IA (110) and labeled alanine into the alanine residue of capreomycin IB (111), discarding the possibility of interconversion between the two polypeptides (260). Moreover, it was observed that labeled (24) and its enantiomer serine is efficiently incorporated into the serine residue of capreomycin IA (110) and labeled alanine into the alanine residue of capreomycin IB (111), discarding the possibility of interconversion between the two polypeptides (260).…”

“…(728) isolated alchorneine (584) from the leaves, roots and bark of Alchornea floribunda (Euphorbiaceae) and from the leaves of Alchornea nintella. Hydrolysis of (586) gave the imidazolidinone (587). Alchorneine (584) was identified by its spectroscopic properties (UV, lH-NMR at 60 MHz, IR and MS) and by chemical degradation.…”

The biosynthesis of plant alkaloids and nitrogenous microbial metabolites

“…Ornithine (1) and putrescine (2) are key early intermediates in the biosynthesis of pyrrolidine alkaloids4v5 and precursors for the polyamines spermine and spermidine (4). The biosynthesis of putrescine in Tetrahymena thermophila (a unicellular eukaryote) has been studJed.…”

“…Tropane alkaloids, e.g. hyoscyamine (7), are formed from ornithine (1) by a biosynthetic sequence which does not involve any symmetrical intermediates such as putrescine (2), and hygrine ( 8) is a late intermediate (results are for D. stramonium and Scopolia 1urida'O.' 1).4*5 The incorporation of [2-I4C]ornithine [as (l)] into hygrine (8) in Nicandra physaloides has been reported to give exclusive labelling of C-2.I0 The incorporation of ornithine into (8) in this plant has been reexamined,'* using DL- [5-14C]omithine.…”