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A PROPOSED MECHANISM FOR THE CRYOAGGREGATION OF THE SEED STORAGE GLOBULIN AND ITS POLYMERIZED FORM FROM TRITICUM AESTIVUM
Author(s) -
MARCONE MASSIMO F.,
YADA RICKEY Y.
Publication year - 1994
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.1745-4514.1994.tb00494.x
Subject(s) - polymerization , circular dichroism , disulfide bond , globulin , chemistry , storage protein , salt (chemistry) , precipitation , cotton effect , crystallography , polymer chemistry , biochemistry , polymer , organic chemistry , biology , physics , meteorology , immunology , gene
The purified salt‐soluble globulin and its polymerized (i.e., polymerized via interchain disulfide bonds between various subunits of differing molecular weights, excluding any interchain disulfide bonds between the 35,000 and 49,000 Da subunits) counterpart from wheat (Triticum aestivum) seed were studied at a variety of temperatures and holding times (i.e., 25, 15, 10C for holding times between 0 and 600 min). A mechanism responsible for cryoaggregation is proposed. The polymerized form of the globulin was found to be much more cryoaggregatable than the nonpolymerized form. Ultraviolet (UV) and circular dichroism (near‐and far‐UV) spectral analyses revealed that the polymerized globulin was more susceptible to conformational changes than its nonpolymerized form with decrease in temperature. It is suggested that the higher flexibility of the polymerized globulin would allow for subtle changes in protein conformation, and therefore, permit the surface aromatic amino acids to interact with other hydrophobic groups on neighboring protein molecules in a cooperative manner. The latter situation may result in aggregation and precipitation.