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Isoelectric Focusing Evidence for Banana Isoenzymes with Mono and Diphenolase Activity
Author(s) -
THOMAS PAUL,
JANAVE M.T.
Publication year - 1986
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.1365-2621.1986.tb11136.x
Subject(s) - isoelectric focusing , isoelectric point , catechol , polyphenol oxidase , chemistry , isozyme , browning , catechol oxidase , chromatography , sephadex , substrate (aquarium) , fractionation , biochemistry , enzyme , biology , peroxidase , ecology
Isoelectric focusing on thin layers of Sephadex G‐75 superfine gel followed by the print technique was used to investigate the presence of polyphenol oxidase isoenzymes in banana fruits. The enzyme preparation from pulp tissues of unripe “Dwarf Cavendish” bananas, partially purified by (NH 4 ) 2 SO 4 fractionation, revealed 14 isoenzymes having both monophenolase (p‐cresol substrate) and diphenolase (dopamine or catechol substrate) functions with isoelectric points (pi) in the pH range 4—5.5. Similarly, two strains of the cv “Red Skin” showed 10 and 13 isoenzymes with pi in the pH range 4–5.8, most of which were capable of hydroxylation of monophenols. Individual isoenzymes exhibited variations in their activity towards mono and odiphenols.