. 2011 Apr 6;286(23):20283–20291. doi: 10.1074/jbc.M111.225979

TABLE 2.

Apparent kinetic parameters of purified SR/GR

Enzyme activity was determined by measuring rates of sulfide production except that of GR, which was determined by measuring decreases in absorbance at 340 nm. K_m^S represents apparent K_m for inorganic sulfur compounds (CS or polysulfide). Data are means of three experiments ± S.E.

Enzyme activity	Substrate	K_m^S	K_m^GSSG	K_m^NADPH	k_cat	k_cat/K_m^S	k_cat/K_m^GSSG	k_cat/K_m^NADPH
		mm	μm	μm	s⁻¹	μm⁻¹s⁻¹	μm⁻¹s⁻¹	μm⁻¹s⁻¹
SR	CS	1.1 ± 0.2	63 ± 8	21 ± 2	200 ± 20	0.18	3.2	9.5
PolySR	Polysulfide	1.2 ± 0.4	70 ± 12	22 ± 3	190 ± 30	0.16	2.7	8.6
GR	GSSG	-^a	55 ± 5	16 ± 2	220 ± 20	-^a	4.0	13.8

^a Not applicable.