TABLE 2.

Kinetic parameters of wild-type and mutants of BbLNBase

Activities of pNP-LNB hydrolysis were measured in 50 mm McIlvaine buffer (pH 4.5) at 30 °C.

Enzyme	Km	kcat	kcat/Km
	×1−6 m	s−1	×103 s−1/m
Wild type	99 ± 11	15 ± 1	160 ± 10
H263F	120 ± 20	0.15 ± 0.01	1.3 ± 0.1
D320A	130 ± 20	0.0068 ± 0.0005	0.052 ± 0.006
D320N	380 ± 50	0.011 ± 0.001	0.028 ± 0.002
Y419F	–a	0.086b	–

^a The K_m value was too low to be determined.

^b The v/[E]₀ value at 100 μm substrate.