The second peptidoglycan hydrolase of Streptococcus faecium ATCC 9790 covalently binds penicillin.

摘要: A second peptidoglycan hydrolase (muramidase-2) of Streptococcus faecium ATCC 9790 (Enterococcus hirae) has been purified to apparent homogeneity. The enzyme shown be a beta-1,4-N-acetylmuramoylhydrolase (muramidase; EC 3.2.1.17) and differ in substrate specificity from previously isolated muramidase. Purified appears as two protein staining bands with molecular masses 125 75 kilodaltons (kDa) on polyacrylamide gels after sodium dodecyl sulfate electrophoresis. Elution renaturation sulfate-polyacrylamide showed that both proteins have muramidase-2 activity. Both bind radioactive benzylpenicillin the same electrophoretic mobilities penicillin-binding 1 5 present membrane preparations this organism, respectively. Incubation [14C]penicillin G-labeled 125-kDa form crude alkaline extracts S. (which did not contain added proteinase inhibitors) endogenous conversion radiolabeled 75-kDa enzyme.