Influence of the extracting solvent upon the structural properties of Amaranth (Amaranthus hypochondriacus) glutelin.
Two amaranth glutelin preparations, Gt-bo extracted with borate buffer at pH 10 and Gt-na extracted with 0.1 N NaOH, were characterized and compared with the amaranth polymerized 11S globulin (Gp, globulin-P). Gt-bo and Gt-na presented very similar polypeptidic composition and a similar reactivity against an anti-Gp polyclonal antibody, although lower than that of Gp. It is demonstrated that Gt-na is composed of denatured and dissociated molecules, whereas Gt-bo consists of folded molecules. The size, polypeptidic composition, thermal stability, and denaturation enthalpy of Gt-bo molecules were similar to those of Gp subjected to a borate treatment at pH 10. The Gp immunoreactivity decreased to the level of Gt reactivity when subjected to alkaline treatment; this could be due to conformational changes. Results suggest that, like Gp, amaranth Gt molecules may be hexameric oligomers of approximately 300 kDa. They would be partially unfolded during the alkaline extraction.
Abugoch
Lilian E
LE
Departamento de Ciencia de los Alimentos y Tecnología Química, Facultad de Ciencias, Universidad de Chile, Vicuña Mackenna 20, Providencia, Santiago, Chile.
Martínez
E Nora
EN
Añón
M Cristina
MC
D027721:Amaranthus / Q000737:chemistry*; D001888:Boric Acids; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005983:Glutens / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010936:Plant Extracts / Q000737:chemistry*; D011489:Protein Denaturation; D017510:Protein Folding; D012997:Solvents; D013816:Thermodynamics
D001888:Boric Acids; D010936:Plant Extracts; D012997:Solvents; D005983:Glutens; C032688:boric acid