OCCURRENCE, PURIFICATION AND PROPERTIES OF THE STAPHYLOCOCCAL BETA-HYDROXYBUTYRATE DEHYDROGENASE

beta-Hydroxybutyrate dehydrogenase (EC 1.1.1.30.) - an enzyme involved in degradation of polymer store material - was found in staphylococci . The enzyme was isolated from Staphylococcus xylosus NCTC D100694 cel ls, purified and characterized. The native enzyme is a tetramer and co nsists of equal subunits. Its relative molecular mass is M(r) = 140 kD a and pI = 4.7. The enzyme activity is stimulated by Mg+2 and Ca+2 ion s. Staphylococcal beta-hydroxybutyrate dehydrogenase is relatively sta ble and active in a wide temperature range. The optimum pH for oxidati on is 8.6 and for reduction 6.7. The enzyme is highly specific for D(- )stereoisomer of beta-hydroxybutyrate. K(m) values for beta-hydroxybut yrate and acetoacetate are 39.1 muM and 5.47 muM, respectively.