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Isolation and characterisation of wheat flour proteins . I.—separation of salt‐ and acetic acid‐dispersible proteins by gel filtration, polyacrylamide gel electrophoresis, and sucrose gradient ultracentrifugation
Author(s) -
Jankiewicz M.,
Pomeranz Y.
Publication year - 1965
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740161103
Subject(s) - chromatography , sephadex , chemistry , acetic acid , size exclusion chromatography , sodium acetate , fractionation , polyacrylamide , polyacrylamide gel electrophoresis , sodium , pyrophosphate , elution , gel electrophoresis , biochemistry , organic chemistry , enzyme , polymer chemistry
Proteins extracted from wheat flour with 0·01 M‐sodium pyrophosphate buffer, pH 7·0, and with 0·05 M‐acetic acid were centrifuged, dialysed against 0·005 M‐sodium acetate buffer pH 4·1, concentrated by ultrafiltration at 4 3 , and lyophylised. The proteins were dispersed in 0·005 M ‐sodium acetate buffer pH 4·1 and fractionated on Sephadex G‐100 and Sephadex G‐200 columns. Based on separation according to average mol. wt. on Sephadex G‐100, the pyrophosphate‐dispersible proteins contained eight, and the following acetic acid‐dispersible proteins six fractions. Proteins extracted directly with 0·05 M ‐acetic acid were separated into seven fractions. The distribution of protein moieties of different average molecular‐size ranges is detailed and shown to be different in the different extracts. Aggregation and disaggregation phenomena were observed during repeated re‐chromatography of high‐ and intermediate‐molecular weight proteins. Ultra‐centrifugation in a stepwise sucrose gradient at 45,000 g. at 4° and fractionation by polyacrylamide‐gel electrophoresis separated the protein into slow‐moving, intermediate‐ and high‐molecular weight moieties. The relative distribution of these moieties was correlated with the mol. wt. of the fractions eluted from Sephadex columns.