Biosynthetic link

Pyridine-2,6-di(monothiocarboxylic acid) (Fig. 26, 73) [for a review, see 36), cf. also (37)] was obtained from Pseudomonas putida (262) and later from Pseudomonas stutzeri (203). It forms a brown Fe " complex and a blue Fe " complex (both FeLig2) (343), wbicb may be accompanied by complexes carrying two additional cyanide ions (345). An X-ray analysis (Plate 6) of tbe Fe " complex of 73 shows a distorted octahedral symmetry (343). There is evidence that a sulfenic acid residue (-CO-SOH) is the biosynthetic link between -COOH and -COSH (344). 

Procter has recently found that the pestalotiopsin skeleton 36 can be converted to the previously unexplored taedolidol natural products upon treatment with acid, suggesting a biosynthetic link between the two families.58... 

Stoltz, B. M., Wood, J. L. The stereoselective ring contraction of a pyranosylated indolecarbazole. A biosynthetic link between K252a and staurosporine Tetrahedron Lett. 1996, 37, 3929-3930. 

An interesting chemical and possible biosynthetic link is that between myoporone and the... 

Attempts to synthesize HIDP by direct oxidation of IDP failed. Preliminary experimentes indicated that an enzymatic oxidation by oxidase is possible, closing a possible biosynthetic link between the opines and amavadin. 

Fig. 8.1 Wong s evolutionary map shows possible relationships between code words. The codons in boxes correspond to today s code words (compare Table 8.1). The codons for Asp and Glu in dotted boxes refer to these amino acids in a very early evolutionary stage of the genetic code. Single-headed arrows refer to the biosynthetic relationships between precursor and product, while double-headed arrows refer to reciprocal formation possibilities. All pairs of codon units (irrelevant of whether they are linked by single- or double-headed arrows) differ only in one single base change (Wong, 1975)...

The biosynthetic origin of the depolymerization-resistant core of cutin (cutan) remains to be established. The early observation that linoleic acid and linolenic acid were preferentially incorporated into the non-depolymerizable core of cutin in apple skin slices suggested that the ether-linked or C-C-linked core might arise preferentially from the czs-l,4-pentadiene system [31]. The insoluble residue, that contained the label from the incorporated polyunsaturated C18 acids, released the label upon treatment with HI, supporting the notion that some of those aliphatic chains were held together by ether bonds. More recently,... 

A repeating unit for S6 was proposed by Rebers and Heidelberger,29 as discussed in Ref. 1. The only features not determined were the structure and configuration of a ribitol phosphate moiety. From biosynthetic considerations,6 the phosphate group should be linked to 0-5 of D-ribitol, and the structure should, therefore, be that depicted in 10. 

The phosphate of ethylene glycol must derive from the ribitol phosphate moiety, which consequently is phosphorylated at a primary position, assumed to be 0-5 of (pro-D)-ribitol for biosynthetic reasons. In the proposed structure for the S10A repeating-unit (14), the anomeric natures of the sugar residues were not determined. The optical rotations of S10A and the hexasaccharide, [a]D +12° and +11°, respectively, indicate that they contain both a- and /3-D-linked sugar residues. 

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