Molybdoenzyme

In the present investigation evidence is presented indicating that the CO₂ reductase from Cl. pasteurianum most probably is a molybdoenzyme: It is synthesized only in the presence of molybdenum and is inactivated by low concentrations of cyanide, as are other molybdoenzymes.

Many organisms possessed several molybdoenzyme families and several subfamilies within these families. In archaea, as in bacteria, DMSOR was also the most frequently used molybdoenzyme family (>95% of Mo-utilizing organisms).

While eukaryotes produce only a limited number of enzymes belonging to the sulfite oxidase and xanthine oxidase families (for instance, four molybdoenzymes are present in humans), enzymes of all three families are present in prokaryotes with enzymes of the DMSO reductase family being predominant.