ISOLATION, CHARATERIZATION AND ARSENATE INHIBITION KINETICS OF ACID PHOSPHATASE FROM Solanum tuberosum TUBERS

Abstract

Acid Phosphatase (EC 3.1.3.2) is a hydrolyase which cleave the phosphate groups from a wide variety of biochemical substrates. Arsenate accumulation in plants and its storage organs is well documented. Potato tuber acid phosphatase was isolated from the tuber and the purification steps includeammonium sulphate precipitation, dialysis and DEAE chromatography. Purified extract yielded a protein band at 57-55 kDa in SDS-PAGE. The enzyme activity assay indicated the Vmax and Km values of 1.85 μmol mg protein-1 min-1 and 10.7 mM respectively when p-nitrophenol was taken as substrate. The phosphatase exhibits tartrate sensitivity. This enzyme exhibits mixed inhibition in presence of arsenate concentration of 10 mM-30mM.