Mobilization of reserve proteins during early stages of seed germination in Fagopyrum esculentum

Abstract

Hydrolysis of 13S globulin, the main storage protein in grains of common buckwheat (Fagopyrum esculentum Moench), proceeds in at least two phases during germination. The first stage, involving a limited proteolytic cleavage of the protein, is associated with increased activity of proteases having maximum activity at pH 7.6. The second stage, involving further hydrolysis of the partially cleaved protein, starts after 12 h of imbibition. During this phase, activity of proteases increased and activity maximum shifted to pH 5.6. Nevertheless, 13S globulin retains its antigenic identity till the emergence of radicle and plumule. Thus, it may not be the major source of amino acids utilized by the germinating seed during the initial stages of imbibition.