the ph dependence of k ( cat ) for the bacillus cereus beta-lactamase i catalyzed hydrolysis of carbenicillin ( vi ) , which differs from benzylpenicillin ( i ) in having a carboxylic moiety alpha to the phenyl ring , exhibits a profile consistent with a model in which the alpha-cooh and alpha-coo forms of the es complex turn over with respective rate constants of 2152 s ( -1 ) and 384 s ( -1 ) .
C0006976
carbenicillin
C0030827
benzylpenicillin