The sulphur oxygenase/reductase (SOR) of the thermo-acidophilic archaeon Acidianus ambivalens is an unusual enzyme consisting of 24 identical subunits arranged in a perfectly symmetrical hollow sphere and containing a mononuclear non-heme iron centre ...
The sulphur oxygenase/reductase (SOR) of the thermo-acidophilic archaeon Acidianus ambivalens is an unusual enzyme consisting of 24 identical subunits arranged in a perfectly symmetrical hollow sphere and containing a mononuclear non-heme iron centre (personal communication: A. Kletzin). At 85 degrees C in vitro, elemental sulphur is oxidised to sulphite, thiosulphate and hydrogen sulphide with no external cofactors needed. The proposed equation is: 4S + O2 + 4 H2O ---> 2 HSO3- + 2 H2S + 2 H+.