Table I.

Steady-State Kinetic Constants for the Hydrolysis of Z-GPR-pNA by Trypsin Variants^a

Variant	kcat (min−1)	KM (µM)	kcat/KM (µM−1 min−1)
WT	4900 ± 100	8 ± 1	610 ± 80
Y39F	6890 ± 90	8.1 ± 0.6	720 ± 60
Y39A	4400 ± 100	7.6 ± 0.9	770 ± 90
K60V	6900 ± 100	9 ± 1	720 ± 90
K60A	5430 ± 80	9 ± 1	600 ± 70

^aKinetic constants were determined at 25°C in 50 mM HEPES, 100 mM NaCl, 20 mM CaCl₂ (pH 8.0) by fitting initial-rate data to the steady-state Michaelis-Menten rate equation [Eq. (1)]. Errors represent the standard deviations described in Figure 1.