TABLE 1.

Kinetic parameters for hydrolysis of six peptide series based on the sequence GRWHTVG ↓ LRWE-Lys(Dnp)-DArg-NH₂ by recombinant human cathepsin S for characterization of all subsites from S3 to S3′

The data represent the means ± S.D. of a triplicate experiment. ↓ represents the only cleavage site. X, norleucin; Cit, citrullin.

Substrate position	Amino acid	Km	Vmax	kcat/Km	Substrate position	Amino acid	Km	Vmax	kcat/Km
		μm	μm/min	1/(s × μm)			μm	μm/min	1/(s × μm)
P-3	F	1.42 ± 0.32	0.450 ± 0.004	4.05	P-1′	F	4.80 ± 0.44	0.206 ± 0.004	0.55
	K	1.94 ± 0.29	0.349 ± 0.006	2.30		K	5.35 ± 1.09	0.071 ± 0.004	0.17
	V	2.76 ± 0.02	0.752 ± 0.011	3.49		V	2.37 ± 0.23	1.005 ± 0.016	5.43
	G	5.14 ± 0.12	0.626 ± 0.005	1.56		Cit	1.71 ± 0.38	0.156 ± 0.003	1.17
	D	1.88 ± 0.09	0.154 ± 0.001	1.05		X	0.73 ± 0.05	0.644 ± 0.027	11.24
	X	1.60 ± 0.24	0.367 ± 0.005	2.95		R	2.44 ± 0.26	0.082 ± 0.001	0.43
	P	3.24 ± 0.32	0.478 ± 0.01	1.89		I	1.98 ± 0.22	0.579 ± 0.011	3.75
	I	0.48 ± 0.09	0.216 ± 0.006	5.82		La	2.37 ± 0.17	0.616 ± 0.009	3.34
P-2	F	2.01 ± 0.09	0.262 ± 0.008	1.67	P-2′	F	5.27 ± 0.35	0.730 ± 0.014	1.78
	K	7.82 ± 0.54	0.136 ± 0.006	0.22		K	1.05 ± 0.12	0.484 ± 0.019	5.91
	T	9.30 ± 1.07	0.133 ± 0.004	0.18		H	3.12 ± 0.01	0.419 ± 0.002	1.72
	Va	2.37 ± 0.17	0.616 ± 0.009	3.34		Q	2.59 ± 0.15	0.637 ± 0.012	3.16
	G	12.86 ± 0.27	0.242 ± 0.005	0.24		D	3.14 ± 0.10	0.455 ± 0.002	1.86
	D	12.37 ± 0.35	0.143 ± 0.002	0.15		Ra	2.37 ± 0.17	0.616 ± 0.009	3.34
	X	4.18 ± 0.16	0.277 ± 0.003	0.85		P	1.31 ± 0.10	0.296 ± 0.004	2.91
	P	5.91 ± 0.29	0.231 ± 0.004	0.50		I	1.50 ± 0.30	0.406 ± 0.009	3.47
	I	3.95 ± 0.44	0.174 ± 0.003	0.57
	M	7.79 ± 0.49	0.536 ± 0.013	0.89
P-1	F	2.58 ± 0.12	0.774 ± 0.012	3.84	P-3′	F	8.20 ± 0.39	0.83 ± 0.010	1.30
	K	27.47 ± 1.65	2.939 ± 0.150	1.37		K	37.87 ± 3.16	0.551 ± 0.031	0.19
	Q	24.90 ± 0.89	3.834 ± 0.230	1.97		H	14.93 ± 0.78	0.179 ± 0.004	0.15
	T	5.06 ± 0.11	1.083 ± 0.020	2.74		G	16.48 ± 0.39	0.299 ± 0.005	0.23
	D	2.80 ± 0.10	0.265 ± 0.009	1.22		Wa	2.37 ± 0.17	0.616 ± 0.009	3.34
	X	10.47 ± 0.59	1.566 ± 0.039	1.92		D	16.68 ± 1.91	0.353 ± 0.030	0.27
	P	19.98 ± 0.75	1.277 ± 0.027	0.82		R	11.54 ± 0.24	0.400 ± 0.006	0.44
	I	5.12 ± 0.36	0.359 ± 0.003	0.90		I	8.20 ± 0.69	0.897 ± 0.004	1.40
	Ga	2.37 ± 0.17	0.616 ± 0.009	3.34

^aThe basis peptide of the library experiment.