title: Delta-1-piperideine-6-carboxylate dehydrogenase, a new enzyme that forms alpha-aminoadipate in Streptomyces clavuligerus and other cephamycin C-producing actinomycetes.
abstract: Delta-1-Piperideine-6-carboxylate (P6C) dehydrogenase activity, which catalyses the conversion of P6C into alpha-aminoadipic acid, has been studied in the cephamycin C producer Streptomyces clavuligerus by both spectrophotometric and radiometric assays. The enzyme has been purified 124-fold to electrophoretic homogeneity with a 26% yield. The native protein is a monomer of 56.2 kDa that efficiently uses P6C (apparent Km 14 microM) and NAD+ (apparent Km 115 microM), but not NADP+ or other electron acceptors, as substrates. The enzyme activity was inhibited (by 66%) by its end product NADH at 0.1 mM concentration. It did not show activity towards pyrroline-5-carboxylate and was separated by Blue-Sepharose chromatography from pyrroline-5-carboxylate dehydrogenase, an enzyme involved in the catabolism of proline. P6C dehydrogenase reached maximal activity later than other early enzymes of the cephamycin pathway. The P6C dehydrogenase activity was decreased in ammonium (40 mM)-supplemented cultures, as was that of lysine 6 amino-transferase. P6C dehydrogenase activity was also found in other cephamycin C producers (Streptomyces cattleya and Nocardia lactamdurans) but no in actinomycetes that do no produce beta-lactams, suggesting that it is an enzyme specific for cephamycin biosynthesis, involved in the second stage of the two-step conversion of lysine to alpha-aminoadipic acid.
authors.affiliation: Area of Microbiology, Faculty of Biology, University of León, 24071 León, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: de La Fuente
authors.forename: A
authors.initials: A
authors.lastname: Rumbero
authors.forename: J F
authors.initials: JF
authors.lastname: Martín
authors.forename: P
authors.initials: P
authors.lastname: Liras
mesh_terms: D015074:2-Aminoadipic Acid / Q000096:biosynthesis*; D001426:Bacterial Proteins; D002513:Cephamycins / Q000096:biosynthesis; D002855:Chromatography, Thin Layer; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D007700:Kinetics; D051306:L-Lysine 6-Transaminase; D008239:Lysine / Q000378:metabolism; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry / Q000378:metabolism*; D010848:Picolinic Acids / Q000378:metabolism*; D010875:Pipecolic Acids / Q000494:pharmacology; D010880:Piperidines / Q000138:chemical synthesis / Q000378:metabolism*; D011758:Pyrroles / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D013302:Streptomyces / Q000201:enzymology* / Q000378:metabolism; D013379:Substrate Specificity; D000637:Transaminases / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002513:Cephamycins; D010848:Picolinic Acids; D010875:Pipecolic Acids; D010880:Piperidines; D011758:Pyrroles; D000644:Quaternary Ammonium Compounds; D009243:NAD; D015074:2-Aminoadipic Acid; C015485:delta-1-pyrroline-5-carboxylate; C008919:delta-1-piperidine-6-carboxylic acid; D000587:Oxidoreductases Acting on CH-NH Group Donors; C109029:delta-1-piperideine-6-carboxylate dehydrogenase; D000637:Transaminases; D051306:L-Lysine 6-Transaminase; C031345:pipecolic acid; D008239:Lysine