Gel filtration under denaturing conditions was used to isolate the alp
ha- and beta-subunits of penicillin acylase (PA). The refolded protein
subunits were obtained on removing urea during dialysis. Preparations
bf both renatured subunits were found to be catalytically active in t
he reaction of hydrolysis of phenylacetic acid p-nitroanilide and this
activity decreased with addition of the serine-specific inhibitor PMS
F. Catalytic activity of the subunits was also measured in reversed mi
celles of Aerosol OT (AOT) in octane, the light (alpha-subunit) being
most catalytically active at w(0) = 11.9 and the heavy (beta-subunit)
at w(0) = 17.5. The positions of the maxima were in good correlation b
oth with theoretically calculated optimal hydration degrees and with;
the earlier reported profile of enzymatic activity for native PA in re
versed micelles.