Resolution and Some Properties of Acid Phosphatase Isozymes Bound to the Cell Wall of Potato Tubers

Abstract

Acid phosphatase bound to the cell wall of potato tubers consists of six isozymes. They were separated from one another by chromatography on DEAE-cellulose, phosphocellulose and Sephadex G-200 columns. No significant differences were observed among these isozymes in pH or temperature dependence of activity and thermal stability, but they were distinct from each other in substrate specificity and sensitivity to several compounds. The isozymes were of non-specific acid phosphatase, and characteristic of high affinity for adenosine 5’-monophosphate as compared with the cytoplasmic type of enzyme. Sugar phosphates or glycerophosphate showed lower affinity, and bis-(p-nitrophenyl)phosphate was only slightly hydrolyzed. The molecular weights of the isozymes were estimated to be 240,000~400,000, based on gel filtration. The reassociation of each isozyme with the cell wall preparation resulted in no change in substrate specificity. The degree of association was affected by the presence of the substrate or hydrolysis product and depended on their concentrations. © 1981, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.