REPRESSIBLE ACID PHOSPHOMONOESTERASE AND CONSTITUTIVE PYROPHOSPHATASE OF SACCHAROMYCES MELLIS

Abstract

Saccharomyces mellisproduced a nonspecific acid phospho-monoesterase (pH optimum of 5.5 to 6.0) when grown in a medium devoid of phosphate. Only minimal amounts of this enzyme are present in cells harvested from media containing phosphate. The enzyme requires no cofactors. It is inhibited by such anions as phosphate, arsenate, molybdate, and borate. S. mellis also contains an inorganic pyrophosphatase with a pH optimum of 7.5. The properties of this enzyme are distinctly different from those of the acid phoaphomonoes-terase. The pyrophosphatase requires Mg++ for activity. This enzyme is constitutive, since it is present in cells regardless of the phosphate content of the growth medium.