Abstract
The enzymatic properties of P2-2 enzyme were determined by using of M.radiodurans. The enzymewas: most active at 60°C incubation temperature, stable at 40°C in neutral buffer, and inactivated by heating at 80°C for 15min. Maximal lytic activity occurred at pH 8.5 in Tris-HCl buffer. The range of enzyme stability was between pH 5.5 and 8. Bivalent metal ions, p-chloromercuribenzoate and monoiodo acetate inhibited lytic activity. The molecular weight was estimated to be 16, 000 daltons by gel filtration on Sephadex G-75. The enzymatic digestion of peptidoglycans from the cell walls of M. radiodurans and M. lysodeikticus liberated free amino groups, but neither reducing groups nor N-acetylhexosamine, indicating that the enzyme was an endopeptidase. From analysis of the N-terminal amino acids of the digests, it is suggested that the P2-2 enzyme cleaves the peptide bond at the carboxyl group of D-alanine in peptidoglycan.
