Dimethylsulfoxide reductase family

Two other families of molybdoenzymes are the sulfite oxidase family6463 13 and the dimethylsulfoxide reductase family.632 641 Nitrogenase (Chapter 24) constitutes a fourth family. Sulfite oxidase (Eq. 16-60) is an essential human liver enzyme (see also Chapter... 

In the case of the DMSO reductase family, as pointed out above, the metal centre is bound to two molecules of the cofactor. DMSO reductase itself catalyses the reduction of dimethylsulfoxide to dimethylsulfide with incorporation of the oxygen atom of DMSO into water. The active site of the oxidized enzyme is an L2MoVI0(0-Ser) centre, which, upon reduction, loses the M=0 ligand to give a L2MoIV(0-Ser) centre. In the catalytic... 

Members of the dimethylsulfoxide (DMSO) reductase family have the molybdenum ligated by two MPTs, one 0x0 group, and the donor atom from the side chain of an amino acid residue—O7 of a serinyl residue (DMSO reductase or trimethylamineoxide (TMAO) reductase), S7 of a cysteinyl residue (dissimilatory nitrate reductase), or Sc7 of selenocys-teinyl residue (formate dehydrogenase). 

The second category includes enzymes that typically catalyze proper oxygen atom transfer reactions to or from an available electron lone pair of a substrate, and can be further subdivided into two families. The first family includes sulfite oxidase and assimilatory nitrate reductase, the physiological functions of which are to reduce nitrate to nitrite in the first stage of its reduction to ammonia for use by the plant cell. The second family comprises bacterial enzymes such as dimethylsulfoxide... 

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