D-Alanine carboxypeptidases of bacillus stearothermophilus: Solubilisation of particulate enzyme and mechanism of action of penicillin

摘要: Abstract Two D -alanine carboxypeptidases have been found to be present in protoplast membranes from Bacillus stearothermophilus . -Alanine carboxypeptidase I removes the terminal residue substrate UDP-MurNAc- L -Ala- -Glu- meso -Dap- -[ 14 C]Ala- C]Ala; (MurNAc, N -acetylmuramyl; Dap, α, e-diaminopimelic acid); II penultimate residue. Both enzymes obtained a soluble form by treatment of with butan-1-ol at 20 °C. The properties membrane-bound state studied. enzyme is inactivated penicillin G but inactivation can reversed β-lactamase. Inhibition shows hyperbolic competitive kinetics. Penicillin does not appear act as analogue and compete for entire active site enzyme. Under certain conditions sensitivity lost without concomitant loss catalytic activity. It suggested that has penicillin-binding separate substrate-binding site, suggestion which strongly supported kinetic evidence.