. Author manuscript; available in PMC: 2014 Mar 15.

Published in final edited form as: J Immunol. 2010 Oct 1;185(9):5360–5368. doi: 10.4049/jimmunol.1002292

Table I.

Comparison of kinetics of chymotryptic (suc-L-Val-Pro-Phe-4NA-hydrolyzing) activity

Enzyme	Buffer	k_cat (s⁻¹)^a	K_m (mM)^a	k_cat/K_m
Mouse Cathepsin G	1.8 M NaCl	41 ± 2	0.12 ± 0.02	330
Mouse Cathepsin G	PBS	33 ± 10	0.20 ± 0.12	170
A²²⁶E Mouse Cathepsin G	1.8 M NaCl	22 ± 2	3.10 ± 0.35	7.1
A²²⁶E Mouse Cathepsin G	PBS	12 ± 2	0.63 ± 0.05	19
S¹⁸⁹A/A²²⁶E Mouse Cathepsin G	1.8 M NaCl	16 ± 2	1.88 ± 0.29	8.5
S¹⁸⁹A/A²²⁶E Mouse Cathepsin G	PBS	9 ± 0	0.37 ± 0.05	24
Human Cathepsin G	1.8 M NaCl	100 ± 7	1.73 ± 0.19	58
Human Cathepsin G	PBS^b	14 ± 0	0.69 ± 0.12	20
Human chymase	1.8 M NaCl	230 ± 35	0.32 ± 0.12	720
Human chymase	PBS^b	17 ± 0	0.29 ± 0.07	59

Mean ± SD, derived from 3 independent measurements at each of 4 substrate concentrations;

as previously determined (48)