Table I.

Kinetic comparisons of peptidyl nitroanilide hydrolysis by chymotryptic peptidases

		AAPF-4NA	AEPF-4NA	RETF-4NA	VPF-4NA
Chymase	kcata	9.3 ± 0.8	8.8 ± 0.2	19.7 ± 0.1	17.2 ± 0.4
	Kma	0.31 ± 0.07	0.15 ± 0.01	0.64 ± 0.05	0.29 ± 0.04
	kcat/Kma	30	59	31	59
+ α2M	kcat	49 ± 2	51 ± 1	87 ± 1	8.9 ± 0.6
	Km	0.28 ± 0.02	0.08 ± 0.08	0.32 ± 0.01	0.16 ± 0.03
	kcat/Km	170	640	270	55
Cathepsin G	kcat	1.4 ± 0.1	3.7 ± 0.8	7.3 ± 11.9	13.8 ± 0.4
	Km	0.97 ± 0.06	0.93 ± 0.08	13 ± 36	0.69 ± 0.07
	kcat/Km	1.4	3.9	0.56	20
+ α2M	kcat	0 ± 0	0.71 ± 0.26	0 ± 0	2.4 ± 2.1
	Km	-	0.12 ± 0.15	-	0.8 ± 1.4
	kcat/Km	-	5.9	-	3.0
Chymotrypsin	kcat	68 ± 8	12.8 ± 0.5	5.0 ± 0.4	11.8 ± 0.4
	Km	0.52 ± 0.14	0.39 ± 0.04	1.1 ± 0.2	0.07 ± 0.01
	kcat/Km	130	33	4.5	170
+ α2M	kcat	48 ± 1	31 ± 1	3.9 ± 0.4	22 ± 1
	Km	0.035 ± 0.003	0.17 ± 0.02	0.057 ± 0.026	0.037 ± 0.007
	kcat/Km	1400	180	68	59

^aUnits of turnover number k_cat, Michaelis constant K_m and specificity constant k_cat/K_m are s⁻¹, mM, and s⁻¹ mM⁻¹, respectively