Streptomyces DD-carboxypeptidases as transpeptidases. The specificity for amino compounds acting as carboxyl acceptors.
The ability of the water-soluble dd-carboxypeptidases of Streptomyces strains albus G, R61, K11 and R39 to perform transpeptidation was studied. The donor was diacetyl-l-lysyl-d-alanyl-d-alanine, and a whole range of amino acids, peptides and structurally related amino compounds were tested for acceptor function. No compound tested was an acceptor for the enzyme from strain albus G whereas the enzymes from strains R61 and K11 could utilize with varying efficiency a wide range of substances including peptides with N-terminal glycine or d-alanine, omega-amino acids, aminohexuronic acids, 6-aminopenicillanic acid and d-cycloserine. Certain peptides, when present in higher concentration, inhibited the transpeptidation observed at lower concentration. The enzyme from strain R39 would not use any dipeptide as an acceptor, but a few compounds that were not glycine or alpha-amino acids of the d-configuration did function thus. These were d-cycloserine and the lactams of meso- or racemic-diaminoadipic acid.
D002247:Carbon Isotopes; D002268:Carboxypeptidases / Q000378:metabolism*; D002854:Chromatography, Paper; D003523:Cycloserine; D004151:Dipeptides / Q000138:chemical synthesis; D004590:Electrophoresis, Paper; D007700:Kinetics; D009842:Oligopeptides / Q000138:chemical synthesis / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D010867:Pimelic Acids; D013302:Streptomyces / Q000201:enzymology*; D013997:Time Factors; D014316:Tritium
D002247:Carbon Isotopes; D004151:Dipeptides; D009842:Oligopeptides; D010455:Peptides; D010867:Pimelic Acids; D014316:Tritium; D003523:Cycloserine; D002268:Carboxypeptidases