title: Biosynthesis of biotin: synthesis of 7,8-diaminopelargonic acid in cell-free extracts of Escherichia coli.
abstract: Cell-free extracts prepared from a biotin auxotroph of Escherichia coli were active in catalyzing the synthesis of 7,8-diaminopelargonic acid, an intermediate of the biotin pathway, from 7-oxo-8-aminopelargonic acid. The product was identified on the basis of its chromatographic characteristics and its biotin activities for biotin auxotrophs of E. coli. Enzyme activity was determined in a reaction coupled with the desthiobiotin synthetase system, which is required for the conversion of 7,8-diaminopelargonic acid to desthiobiotin, and by measuring the amount of desthiobiotin formed by microbiological assay. The reaction was stimulated by l-methionine and pyridoxal-5'-phosphate. l-Methionine could not be replaced by any other amino acids tested. Pyridoxamine and pyridoxamine-5'-phosphate were as active as pyridoxal phosphate. The enzyme, presumably an aminotransferase, was demonstrable in the parent strain of E. coli and all mutant strains tested with the exception of a strain which is able to grow on diaminopelargonic acid but not on 7-oxo-8-aminopelargonic acid. Furthermore, the enzyme was repressible by biotin. The results were consistent with the hypothesis that the biosynthesis of 7,8-diaminopelargonic acid from 7-oxo-8-aminopelargonic acid is an obligatory step in the biosynthetic pathway of biotin in E. coli.
mesh_terms: D000588:Amines / Q000096:biosynthesis*; D001681:Biological Assay; D001710:Biotin / Q000032:analysis / Q000096:biosynthesis* / Q000494:pharmacology; D002474:Cell-Free System; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002621:Chemistry; D002854:Chromatography, Paper; D002855:Chromatography, Thin Layer; D003956:Dialysis; D004794:Enzyme Repression; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism*; D005227:Fatty Acids / Q000096:biosynthesis*; D008025:Ligases / Q000378:metabolism; D008715:Methionine / Q000378:metabolism; D009154:Mutation; D011732:Pyridoxal Phosphate / Q000378:metabolism; D000644:Quaternary Ammonium Compounds; D013053:Spectrophotometry; D013431:Sulfates; D000637:Transaminases / Q000378:metabolism
chemical_list: D000588:Amines; D005227:Fatty Acids; D000644:Quaternary Ammonium Compounds; D013431:Sulfates; D011732:Pyridoxal Phosphate; D001710:Biotin; D008715:Methionine; D000637:Transaminases; D008025:Ligases