a new beta-lactam sulfone , cp 45899 , has been proved to be a time-dependent irreversible inhibitor of three r-factor-mediated beta-lactamases ( penicillin amido-beta-lactamhydrolase , ec 3.5.2.6 ) : tem-1 ( pi = 5.4 ) , tem-2 ( pi = 5.6 ) and pitton 's type 2 ( pi = 7.7 ) .
C0282215
beta-lactam
C0030842
penicillin