Reactions were performed in 2.5 mL 100 mM phosphate buffer pH 8.0 containing
5% acetone, 1.5 mM p-NPA or p-NPB and 150 L of the supernatant
fraction. Absorbance was continuously recorded for 60 s at 400 nm.
Specific activity was calculated using the molar extinction coeffi-
cientforp-nitrophenol(18.6 mM−1 cm−1) andexpressedasmoles
of substrate hydrolyzed per min per mg of protein.