Amaranth globulin structure modifications induced by enzymatic proteolysis.
Globulin-P was partially hydrolyzed with papain under specific conditions to study the resulting structural modifications. Under mild hydrolytic conditions, globulin-P polymers were cleaved to render their unitary constituents (280 kDa molecules). Under stronger hydrolytic conditions these unitary molecules were 13% smaller than those from nonhydrolyzed globulin. Moreover, these molecules remained assembled even though they contained degraded polypeptides. The monomeric (M) subunit and the A chains were preferentially cleaved under mild and intermediate hydrolytic conditions, whereas B chains remained with the same size. These results suggest that the M and A polypeptides might be located at an exposed site of the molecules resembling the structure of the legumins. The M subunit may be participating in the stabilization of globulin-P polymers, on the basis that these two species disappeared under the same hydrolytic conditions. Similar events such as those described in this paper might be taking place on globulin-P during germination of amaranth grain.
Castellani
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Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 47 y 116 Argentina.
Martínez
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Añón
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MC
D002523:Edible Grain; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005916:Globulins / Q000737:chemistry* / Q000302:isolation & purification; D010206:Papain; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification; D012639:Seeds / Q000737:chemistry*
D005916:Globulins; D010940:Plant Proteins; D010206:Papain