Table 1A.

Kinetic constants for cleavage of the fluorogenic substrate Ala-Pro-AFC and the chromogenic substrate Gly-Pro-pNA by wild-type DPPIV and DPPIV glycosylation mutants (proteins expressed in Sf9 insect cells)

DPPIV mutant	Km (μM)	kcat (sec−1)	kcat/Km (M−1sec−1)	Relative kcat/Km
Kinetic constants for cleavage of Ala-Pro-AFC
Wild-type DPPIV	14	18	1.3 × 106	1.0
DPPIV-N85A	15	16	1.1 × 106	0.85
DPPIV-N92A	14	18	1.3 × 106	1.0
DPPIV-N150A	14	18	1.3 × 106	1.0
DPPIV-N219A	15	18	1.2 × 106	0.92
DPPIV-N229A	14	12	9.1 × 105	0.70
DPPIV-N281A	14	15	1.1 × 106	0.85
DPPIV-N321A	14	9	6.5 × 105	0.50
DPPIV-N520A	14	13	8.9 × 105	0.68
DPPIV-N685A	13	19	1.4 × 106	1.1
Kinetic constants for cleavage of Gly-Pro-pNA
Wild-type DPPIV	170	20	1.2 × 105	1.0
DPPIV-N85A	155	16	1.1 × 105	0.92
DPPIV-N92A	147	19	1.3 × 105	1.1
DPPIV-N150A	143	19	1.3 × 105	1.1
DPPIV-N219A	144	19	1.3 × 105	1.1
DPPIV-N229A	151	13	8.8 × 104	0.73
DPPIV-N281A	159	17	1.1 × 105	0.92
DPPIV-N321A	156	10	6.5 × 104	0.54
DPPIV-N520A	142	14	9.6 × 104	0.80
DPPIV-N685A	152	21	1.4 × 105	1.2