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 cells, purified and characterized. The native enzyme is a tetramer and consists of equal subunits. Its relative molecular mass is M(r) = 140 kDa and pI = 4.7. The enzyme activity is stimulated by Mg+2 and Ca+2 ions. Staphylococcal beta-hydroxybutyrate dehydrogenase is relatively stable and active in a wide temperature range. The optimum pH for oxidation is 8.6 and for reduction 6.7. The enzyme is highly specific for D(-)stereoisomer of beta-hydroxybutyrate. K(m) values for beta-hydroxybutyrate and acetoacetate are 39.1 muM and 5.47 muM, respectively.