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Storage Proteins of Glandless Cottonseed Flour
Author(s) -
ZARINS Z. M.,
CHERRY J. P.
Publication year - 1981
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.1365-2621.1981.tb04503.x
Subject(s) - size exclusion chromatography , chromatography , chemistry , fraction (chemistry) , cystine , methionine , cottonseed , tryptophan , polyacrylamide gel electrophoresis , gel electrophoresis , molecular mass , amino acid , biochemistry , cysteine , food science , enzyme
The salt‐soluble storage protein isolate of defatted glandless cottonseed flour was separated by gel filtration column chromatography into six fractions (I to VI). Column and thin‐layer gel filtration showed that these fractions had molecular weights of >600,000, 280,000, 127,000, 63,500, 10,700, and <2,000, respectively. Treating fraction I protein with dilute alkali dissociated a component that migrated upon gel filtration with fraction VI. Both fractions I and VI were yellow and the color intensified at alkaline pH, suggesting the presence of bound flavonol and gossypol pigments. Because of its large size and low (16.6%) protein content, fraction I was thought to be fragments of membrane and aleurone gram globulins. Gradient polyacrylamide gel electrophoresis (PAGE) showed that the proteins in each fraction being completely recovered from column chromatography were represented in the pattern of the initial isolate. The proteins in fractions II and III have similar ammo acid compositions, except that III is low in methionine, cystine and tryptophan and II is low in tyrosine and phenylalanine. The amino acid composition of fraction I was also similar to fractions II and III, while unique patterns were noted for fractions V and VI. Fraction VI was rich in lysine and arginine.