Structural and Kinetic Characterization of Hyperthermophilic NADH-Dependent Persulfide Reductase from Archaeoglobus fulgidus

Table 2

Steady-state kinetics of AfNpsr under aerobic conditions at 70°C.

Substrate^a	(s^-1)	(mM)	(M^-1 s^-1)
NADH^b
NADPH^b	NR^c	—	—
DTNB
Coenzyme A disulfide	NR	—	—
Glutathione disulfide	NR	—	—
Cystine	NR	—	—
Coenzyme A persulfide
Glutathione persulfide
Cysteine persulfide
Polysulfide^d

^aAll reactions performed with di-, per-, and polysulfide substrates contained 100 μM NADH. ^bNAD(P)H oxidase activity. No di-, per-, or polysulfides were present. ^cNR: no reaction. ^dThe reaction was performed in 1 M Tris, pH 8.7, as in (8).