[DsrC protein]-disulfide + hydrogen sulfide + 2 A + 3 H2O = [DsrC protein]-dithiol + sulfite + 2 AH2 + H(+)
[dsrc protein]-disulfide + hydrogen sulfide + 2 a + 3 h2o = [dsrc protein]-dithiol + sulfite + 2 ah2 + h(+)