title: Incorporation of labeled precursors into A16886B, a novel  -lactam antibiotic produced by Streptomyces clavuligerus.
abstract: The incorporation of C-14 from amino acids into A16886B, 7-(5-amino-5-carboxyvaleramido)-7-methoxy-3-carbamoyloxymethyl-3-cephem-4- carboxylic acid, by Streptomyces clavuligerus is reported. As with cephalosporin C biosynthesis by the mold Cephalosporium acremonium, labels from cysteine, valine, and alpha-amino-adipic acid were incorporated. Unlike cephalosporin C, in A16886B label from lysine was incorporated into the alpha-aminoadipic acid side chain. Label from methionine-(14)C-methyl was incorporated into the methoxyl group. The relative percentage of incorporation of (3)H and (14)C from doubly labeled cystine suggests the improbability of the C-7 methoxyl group arising from an intermediate containing a double bond between C-6 and C-7.
mesh_terms: D000577:Amides / Q000096:biosynthesis; D000596:Amino Acids / Q000378:metabolism; D002247:Carbon Isotopes; D002511:Cephalosporins / Q000096:biosynthesis / Q000378:metabolism*; D002854:Chromatography, Paper; D003470:Culture Media; D006868:Hydrolysis; D007769:Lactams / Q000378:metabolism; D013302:Streptomyces / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014316:Tritium
chemical_list: D000577:Amides; D000596:Amino Acids; D002247:Carbon Isotopes; D002511:Cephalosporins; D003470:Culture Media; D007769:Lactams; D014316:Tritium