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ISOLATION AND CHARACTERIZATION OF THE 11S GLOBULIN FROM AMARANTH SEEDS
Author(s) -
CHEN SANFENG,
PAREDESLOPEZ OCTAVIO
Publication year - 1997
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.1745-4514.1997.tb00224.x
Subject(s) - amaranth , amaranthus hypochondriacus , size exclusion chromatography , protein subunit , chromatography , globulin , chemistry , denaturation (fissile materials) , sedimentation equilibrium , ionic strength , electrophoresis , sedimentation coefficient , biochemistry , polyacrylamide gel electrophoresis , molecular mass , gel electrophoresis , biology , enzyme , ultracentrifuge , nuclear chemistry , aqueous solution , immunology , gene
Globulins of Amaranthus hypochondriacus were extracted with two different buffer systems which varied in ionic strength. SDS‐PAGE analysis demonstrated that subunit patterns were different between the two extracting systems. Amarantin, the native 11S globulin of amaranth, and its subunits were purified by gel filtration chromatography and preparative electrophoresis. The native amarantin exhibited two heterogeneous forms of MW 330 and 400 kDa, which yielded the same subunit composition after reduction. SDS‐PAGE analysis showed that prior to reduction, the 50–52 kDa subunit was the major band, and that after reduction, two new bands of 32–34 kDa and 22–24 kDa appeared. This is a typical characteristic of 11S proteins whose subunits consist of an acidic polypeptide (27–37 kDa) and a basic polypeptide (20–24 kDa) linked by a disulfide bond . Ultracentrification analysis showed that amarantin has a 11.9S sedimentation coefficient whereas DSC demonstrated that the denaturation temperatures in the presence of H 2 O, Tris‐HCl and K 2 HPO 4 ‐KH 2 PO 4 are 99C, 99.8C and 103C, respectively .