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Polyphenol Qxidase of Kiwifruit
Author(s) -
PARK E. Y.,
LUH B. S.
Publication year - 1985
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1985.tb13771.x
Subject(s) - polyphenol oxidase , chemistry , browning , chromatography , catechin , ascorbic acid , actinidia chinensis , column chromatography , fractionation , polyacrylamide gel electrophoresis , polyphenol , dehydroascorbic acid , biochemistry , botany , food science , enzyme , biology , peroxidase , antioxidant
Polyphenol oxidase in kiwifruit (Actinidia chinensis planch) was extracted and purified through (NH 4 ) 2 SO 4 fractionation, dialysis and chromatography on DEAE‐cellulose column. Polyacrylamide disc‐gel electrophoresis showed eight bands with oxidase activity. The molecular weight of the dominant isozyme was 25,000 as determined by gel electrophoresis. The cresolase fraction appeared in the first peak (FA1P) and catecholase in the fourth peak (FA4P) when eluted from a DEAE‐cellulose column. The optimum pH of the FA4P fraction was 7.3. The Km value was 50 mM (+) catechin for FA1P and 8.7 mM for FA4P. Ascorbic acid delayed enzymic browning in kiwi fruit. The activation energy with (+) catechin as substrate was 4.0 Kcal/mole for FA1P and 7.0 Kcal/mole for FA4P.