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COMPARISON OF PEROXIDASES FROM BARLEY KERNEL ( Hordeum vulgare L.) AND WHEAT GERM ( Triticum aestivum L.): ISOLATION AND PRELIMINARY CHARACTERIZATION
Author(s) -
BILLAUD CATHERINE,
LOUARME LOÏC,
NICOLAS JACQUES
Publication year - 1999
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1999.tb00011.x
Subject(s) - hordeum vulgare , peroxidase , guaiacol , chemistry , fractionation , point of delivery , hydrogen peroxide , chromatography , ion chromatography , isoelectric focusing , enzyme , biochemistry , biology , poaceae , botany
Peroxidases (POD) of crude extracts from barley and wheat germ were separated, partially purified using salt fractionation, ion‐exchange and hydrophobic interaction chromatographies and their properties examined. Barley and wheat germ POD contained basic, neutral and anionic isoforms as confirmed by isoelectric focusing. Toyopearl‐Butyl 650 M chromatography resolved POD into four cationic fractions. Chromatography of wheat germ extract on CM‐Sepharose isolated an anionic and a neutral fraction. Following chromatography on Concanavalin‐A Sepharose, enzymes from both cereals showed differences in their elution properties. Optimum pH ranges were 4.0 to 5.5 (barley) and 5.3 to > 6.3 (wheat germ) and POD reacted differently under acidic or basic conditions. Their catalytic behavior in the presence of calcium also differed. Kinetics of POD were of Michaelian type with a ping‐pong mechanism and Michaelis constants of guaiacol oxidation in the presence of hydrogen peroxide varied from one enzymatic group to another.