TY - JOUR T1 - Purification and Some Properties of a Polyphenol Oxidase from Koshu Grapes JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 122 LP - 127 DO - 10.5344/ajev.1983.34.2.122 VL - 34 IS - 2 AU - Kazuo Nakamura AU - Yoshifumi Amano AU - Motoo Kagami Y1 - 1983/01/01 UR - http://www.ajevonline.org/content/34/2/122.abstract N2 - Polyphenol oxidase (EC 1.10.3.1) was extracted from an acetone powder prepared from Koshu grapes. The enzyme was purified 172-fold by ammonium sulfate fractionation followed by three successive column chromatographies on O-(carboxymethyl) cellulose, O-(diethylaminoethyl) cellulose and hydroxylapatite. The purified enzyme was homogeneous on polyacrylamide gel electrophoresis. The molecular weight of this enzyme was estimated to be 39 000 - 41 000 by gel filtration and sodium dodecyl sulfate polyacrylamide gel electrophoresis, and the enzyme molecule had no subunit. The temperature and pH optima were 25°C and 6.0, respectively. The enzyme was stable in the alkaline pH range (between pH 7.0 and pH 11.0) and at temperatures up to 30°C. The enzyme exhibited high activity toward o-diphenolic compounds and showed no activity toward monophenols. ER -