the function of the hydroxyl group of the tyrosine residue readily nitrated by tetranitromethane ( tyrosine-105 ) in the rtem plasmid-derived beta-lactamase ( penicillinase ; penicillin amido beta-lactam-hydrolase , ec 3.5.1.6 ) from e. coli and in bacillus cereus beta-lactamase i has been investigated by chemical modification methods .
C0030841
penicillinase
C0597979
beta-lactam-hydrolase