Purification, carbohydrate composition and kinetic properties of the constitutive yeast acid phosphatase.

Constitutive acid phosphatase was purified from yeast cells grown in a medium supplied with 100 mM phosphate. Specific activity of the pure enzyme was 63.5 mumol/min X mg. The enzyme contains 42.5% of protein, 55% of mannose and 2.5% of N-acetylglucosamine. The carbohydrate chains are N-glycosidically linked to the protein. The pure enzyme shows non-linearity in the Lineweaver-Burk plot, thus indicating the presence of two enzyme forms with Km values of about 0.65 mM and 8.5 mM. The pH optimum of the enzyme is at pH 3.3. The enzyme is much more sensitive to heat denaturation than the repressible acid phosphatase.