Table 1.

Apparent pKa values of relevant catalytic residues in WT α-sarcin, L145F mutant, and RNase T1

Residue	WT	L145F	RNase T1a
His 50	7.7 ± 0.2	7.9 ± 0.2	7.9 ± 0.01
Glu 96	5.2 ± 0.1	5.0 ± 0.1	4.3 ± 0.05
His 137	5.8 ± 0.1	7.1 ± 0.1	7.8 ± 0.01

^a The equivalent residues to H50, E96, and H137 of α-sarcin in RNase T1 are H40, E58, and H92, respectively. Values from Inagaki et al. (1981).

(WT) Wild type.