PURIFICATION AND CHARACTERIZATION OF BASIC ASCORBATE OXIDASE FROM SATSUMA MANDARINE (CITRUS-UNSHIU MARC)

Basic ascorbate oxidase of the multiple enzyme forms existing in young fruit of satsuma mandarin (Citrus unshiu Marc) has been separated and subsequently purified to electrophoretic homogeneity through (NH4)(2) SO4 fractionation and chromatographies on DEAE-Toyopearl 650M, CM-Seph adex C-50 and Sephadex G-100. The native molecular weight was estimate d to be 141 kDa by gel filtration and composed of two non-identical su bunits with an apparent mass of 74 kDa and 62 kDa. The optimum pH was found to be 55 with reasonable stability between pH 5 and 8. The enzym e had an optimum temperature at 45 degrees C and was stable up to 50 d egrees C upon heat treatment for 5 min. The presence of sodium diethyl dithiocarbamate, metabisulphite and potassium cyanide completely inhib ited the enzyme activity. Fluoride also inhibited the activity substan tially at higher concentrations. Other monovalent and divalent metal i ons did not have inhibitory effects.