Isoenzymes of human erythrocyte acid phosphatase

Abstract

1. 1. Human erythrocyte acid phosphatases of the two most frequently occurring phenotypes, B and BA, have been purified and resolved into five and seven components, respectively, by the use of a procedure that includes adsorption on Ca 3(PO 4) 2 Sephadex gel filtration and DEAE-cellulose column chromatography. 2. 2. The use of 4-methylumbelliferyl phosphate as a fluorogenic substrate for the visualisation of the isoenzymes on starch gel greatly increases the sensitivity of the technique and reveals more complex patterns of enzymic activity than had previously been described. 3. 3. Gel filtration experiments suggest a molecular weight of 13 000 for all of the purified components of the B phenotype. 4. 4. The isoenzymes appear similar when their substrate specificities were examined but differed with respect to their K m values and their pH optima. 5. 5. Multiple forms of this acid phosphatase do not seem to arise from variations in sialic acid content.