Catalyzes the CoA-dependent reduction of elemental sulfur (S(0)) to produce hydrogen sulfide. Can use both NADPH and NADH, but shows a preference for NADPH (PubMed:24723088). CoA-SH may act to solubilize S(0) by forming CoA persulfides, followed by the reduction of an enzyme-S-S-CoA intermediate produced after both enzymatic and nonenzymatic evolution of H(2)S from the CoA persulfide (PubMed:24723088). Also catalyzes the oxidation of NADPH as well as NADH and predominantly converts O(2) to H(2)O, with a preference for NADPH (PubMed:23453203). hydrogen sulfide + NADP(+) = NADPH + sulfur hydrogen sulfide + NAD(+) = NADH + sulfur 2 H(+) + 2 NADPH + O2 = 2 H2O + 2 NADP(+) 2 H(+) + 2 NADH + O2 = 2 H2O + 2 NAD(+) Binds 1 FAD per subunit. kcat is 68 sec(-1) for NADH oxidase activity. kcat is 50 sec(-1) for NADPH oxidase activity. Optimum pH is 8.0 for NAD(P)H oxidase activity. Highly thermostable. Homohexamer. Belongs to the class-III pyridine nucleotide-disulfide oxidoreductase family.