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THE MOLECULAR WEIGHT OF A BEER PROTEIN‐POLYSACCHARIDE FRACTION
Author(s) -
Simmonds D. H.
Publication year - 1966
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1966.tb03007.x
Subject(s) - sedimentation coefficient , ultracentrifuge , chromatography , chemistry , ionic strength , fraction (chemistry) , elution , molecular mass , polysaccharide , sedimentation equilibrium , sedimentation , concentration gradient , ion exchange , analytical chemistry (journal) , ion , biochemistry , enzyme , organic chemistry , biology , paleontology , sediment , aqueous solution
The high molecular weight components of beer were separated into two groups by chromatography on DEAE‐cellulose equilibrated to pH 7·5. One fraction was only slightly retarded by the anion exchanger, while the second group was retained and could be eluted by a gradient of decreasing pH and increasing ionic strength. Each group contained both protein and polysaccharide components. The behaviour of the two fractions was studied in the ultracentrifuge. Both were polydisperse and diffused rapidly. At a concentration of 2·08%, the unretained group moved as a single, rapidly diffusing peak with an apparent sedimentation coefficient, s 20, w = 1·50 S. The major component of the retained group, Peak G, showed the presence of a second, faster‐moving component. At a concentration of 1·01%, the main peak had a apparent sedimentation coefficient, s 20, w = 2·30 S. The unretained fraction (A), was studied by the sedimentation equilibrium technique. Its weight average molecular weight at the meniscus was found to decrease with time from 19,600 to 9,650 during the course of the experiment, suggesting marked heterogeneity.