p-Hydroxymercuribenzoate is a non-competitive inhibitor of beta-lactamase I from Bacillus cereus and also, after preliminary preincubation, an inactivator of the enzyme. Submitted to the simultaneous action of PCMB plus dicloxacillin, the enzyme completely loses its activity. Extensive dialysis can restore the enzymatic activity only if preincubation had been carried out with either PCMB or dicloxacillin but not if both inhibitors had been simultaneously present. Mercaptoethanol protects the enzyme from the action of PCMB, but not from the severe inactivation caused by dicloxacillin-PCMB mixtures. All these data suggest the formation of a complex between PCMB and the acyl-enzyme intermediate generated upon hydrolysis of the beta-lactam bond of dicloxacillin.
ON THE FORMATION OF A DICLOXACILLIN-PARA-HYDROXYMERCURIBENZOATE SUICIDE COMPLEX MEDIATED BY BETA-LACTAMASE-I FROM BACILLUS-CEREUS / G., Amicosante; A., Oratore; M. C., Marinucci; M. I., Tizzani; Scazzocchio, Francesca; Crifo', Carlo; Strom, Roberto. - In: BIOCHEMISTRY INTERNATIONAL. - ISSN 0158-5231. - STAMPA. - 14:(1987), pp. 15-26.
ON THE FORMATION OF A DICLOXACILLIN-PARA-HYDROXYMERCURIBENZOATE SUICIDE COMPLEX MEDIATED BY BETA-LACTAMASE-I FROM BACILLUS-CEREUS
SCAZZOCCHIO, Francesca;CRIFO', Carlo;STROM, Roberto
1987
Abstract
p-Hydroxymercuribenzoate is a non-competitive inhibitor of beta-lactamase I from Bacillus cereus and also, after preliminary preincubation, an inactivator of the enzyme. Submitted to the simultaneous action of PCMB plus dicloxacillin, the enzyme completely loses its activity. Extensive dialysis can restore the enzymatic activity only if preincubation had been carried out with either PCMB or dicloxacillin but not if both inhibitors had been simultaneously present. Mercaptoethanol protects the enzyme from the action of PCMB, but not from the severe inactivation caused by dicloxacillin-PCMB mixtures. All these data suggest the formation of a complex between PCMB and the acyl-enzyme intermediate generated upon hydrolysis of the beta-lactam bond of dicloxacillin.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.