Ferrous- or cobalt ion-dependent D-(-)-tartrate dehydratase of pseudomonads: purification and properties.

D-(-)-Tartrate dehydratases [D-(-)-tartrate hydro-lyase, EC 4.2.1...] were isolated from two Pseudomonas strains. The molecular weights of the native enzymes were determined to be 72,000 and 7 8,000, respectively, and each enzyme was composed of two subunits of identical size. The dehydratases had no requirements for thiol compounds, were insensitive to oxygen, and required Fe2+ (0.1 mM) or Co2+ (0.5 mM) ions for optimal activity.