Table 1. Formation of DC—β-casein_161–175 peptide conjugate and release of NH₃ by WT and Trp-241 mutant TG2.

	Formation of DC—β-casein161-175 peptide conjugate						NH3 release
Enzyme	Km, mM	ΔΔGbinding, kcal·mol-1	kcat, s-1	ΔΔGcatalysis, kcal·mol-1	kcat/Km, s-1·mM-1	ΔΔGT‡, kcal·mol-1	kcat, s-1	ΔΔGcatalysis, kcal·mol-1	kcat/Km, s-1·mM-1	ΔΔGT‡, kcal·mol-1
WT	1.45 ± 0.06		2.450 ± 0.034		1.69		3.74		2.58
W241Y	2.12 ± 0.24	0.23	0.149 ± 0.008	1.74	0.069 (25)	1.97	0.138	2.03	0.065 (40)	2.27
W241F	3.49 ± 0.34	0.54	0.082 ± 0.008	2.10	0.023 (70)	2.65	0.199	1.81	0.057 (45)	2.35
W241H	3.26 ± 0.40	0.50	0.031 ± 0.005	2.64	0.010 (165)	3.14	0.088	2.31	0.027 (95)	2.81
W241A	2.31 ± 0.16	0.29	0.008 ± 0.0003	3.50	0.0036 (470)	3.79	0.018	3.29	0.008 (320)	3.56
W241G	2.12 ± 0.19	0.23	0.006 ± 0.0004	3.72	0.0028 (615)	3.95	<0.017	>3.32	<0.008 (>320)	>3.56

Kinetic constants and ΔΔG values were determined as described (see Materials and Methods). Values represent means ± SEM of triplicate determinations. Values in parentheses represent the fold decrease relative to WT.