Table 2.

Kinetic constants for inactivation of AChE^a, and for the hydrolysis of compounds 17-24 using mutants of phosphotriesterase.^b

Compound	Inactivation rate constant kinact/KI, (M−1 min−1)	wild-type	G60A	YT kcat/Km (M−1 s−1)	BHR-30	BHR-72
(SCSP)-17	(1.8 × 10⁸)c	<1 × 102	<3 × 10¹	3.9 × 105	1.4 × 106	4.1 × 104
(SCRP)-17		2.1 × 104	1.7 × 104	<1 × 103	1.4 × 106	4.1 × 104
(SCSP)-18	3.9 × 103	<1 × 102	<1.5 × 102	2.8 × 103	<1.5 × 102	<1 × 102
(SCRP)-18		1.3 × 104	4.3 × 104	2.8 × 103	3.3 × 103	3.9 × 103
(SCRP)-19	8.6 × 105	6.8 × 103	<1 × 103	1.3 × 105	3.4 × 104	2.5 × 104
(SCSP)-19		7.0 × 104	4.1 × 105	<1 × 103	5.7 × 105	2.5 × 104
(SCSP)-20	1.2 × 103	<1 × 103	<1 × 103	<1 × 102	<1 × 103	<1.0 × 103
(SCRP)-20		5.9 × 103	2.4 × 104	<1 × 102	4.5 × 103	4.0 × 103
(SCSP)-21	3.3 × 101	<2 × 102	<6 × 102	3.7 × 103	<2 × 102	<2 × 102
(SCRP)-21		5.9 × 103	3.2 × 104	<2 × 102	1.4 × 104	3.9 × 103
(SCSP)-22	NOd	<2 × 102	<6 × 102	2.2 × 102	<2 × 102	<2 102
(SCRP)-22		2.6 × 103	8.3 × 103	2.2 × 102	7.3 × 102	4.5 × 102
(SCRP)-23	2.2 × 102	<5 × 102	<1 × 103	1.4 × 103	<3 × 102	<3.0 × 102
(SCSP)-23		5.8 × 104	7.3 × 106	<3 × 102	3.3 × 105	1.0 × 105
(SCSP)-24	NO	<2 × 102	<1 × 103	<3 × 102	<3 × 102	<3 × 102
(SCRP)-24		1.4 × 103	2.3 × 104	<3 × 102	1.7 × 103	9.1 × 102
(RCSP)-17	(2.8 × 10⁸)c	3.6 × 103	<3 × 10¹	3.9 × 105	1.4 × 106	4.1 × 104
(RCRP)-17		2.1 × 104	6.0 × 10⁴	8.4 × 104	1.4 × 106	4.1 × 104
(RCSP)-18	1.0 × 103	<1 × 102	<1.5 × 102	1.8 × 103	1.1 × 103	2.4 × 103
(RCRP)-18		1.3 × 104	3.9 × 104	1.8 × 103	5.0 × 103	2.4 × 103
(RCRP)-19	2.9 105	8.2 × 103	<1 × 103	1.0 × 105	9.5 × 104	1.5 × 104
(RCSP)-19		2.7 × 104	4.5 × 105	3.1 × 103	5.8 × 105	6.3 × 104
(RCSP)-20	4.4 × 102	<1 × 103	<1 × 103	<1 × 102	<1 × 103	<5 × 103
(RCRP)-20		2.2 × 104	2.6 × 105	<1 × 102	2.2 × 104	9.6 × 103
(RCSP)-21	3.2 × 102	2.4 × 103	<6 × 102	2.0 × 104	3.0 × 103	5.2 × 103
(RCRP)-21		8.9 × 104	2.2 × 105	6.9 × 102	5.5 × 104	2.1 × 104
(RCSP)-22	NO	<2 × 102	<6 × 102	<2 × 102	<2 × 102	<2 × 102
(RCRP)-22		5.7 × 104	1.5 × 105	2.6 × 102	6.0 × 103	2.1 × 103
(RCRP)-23	8.5 × 102	1.7 × 103	<1 × 103	2.6 × 103	5.9 × 102	8.5 × 102
(RCSP)-23		2.9 × 106	1.0 × 107	2.6 × 103	6.1 × 105	5.0 × 105
(RCSP)-24	NO	<5 × 102	<1 × 103	<3 × 102	<3 × 102	<5 × 102
(RCRP)-24		7.2 × 104	2.2 × 106	<3 × 102	2.8 × 104	7.1 × 103

^apH 8.0 and 25 °C

^bpH 9.0 and 30 °C.

^creferences 5 and 7.

^dNO, not observed.