REVEALING ACTIVE-SITE ON THE LIGHT SUBUNIT OF PENICILLIN ACYLASE

Serine-specific irreversible inhibitor phenylmethanesulfonyl fluoride (PMSF) inactivates penicillin acylase subunits, which were chromatographically separated under denaturing conditions and refolded by dialysis, in aqueous solution and Aerosol OT reversed micelles. The activities of both alpha and beta subunits decrease with increasing PMSF concentration but the dependence is no longer linear, in contrast with the native enzyme. The enzyme inactivated in aqueous solution, when solubilized in the micellar system at Wo=12, exhibits an additional activity, which can be further inhibited by PMSF.