Role of Proteinases in the Degradation of the Major Storage Proteins of Linseed Germinating Seeds

Abstract

The proteolytic activities of the germinating linseed using casein, azocoll and linseed globulin as substrates showed a steady increase until 48 hr of germination, followed with a rapid increase to reach a peak after 3 days lag of germination and then declined again. While caseinolytic activity is significantly correlated with the percent of degradation of the major globulin bands through out germination, endopeptidase measured with azocoll as substrate and autodigestive activities are significantly correlated with some bands and not with the others. Caseolytic, endopeptidase, autodigestive activities are significantly correlated with the percent of degradation of the major globulin bands in the period of germination from 48 hr until 84 hr. The two exopeptidases investigated have shown different patterns. The carboxypeptidase was very active in the early period of germination, while aminopeptidase was active at the later stages. The activities of exopeptidases are significantly correlated with the amino acids content in the period of germination where the exopeptidase are at their maximum activities. This indicated their active role in the mobilization of the major globulin protein. In conclusion both the exopeptidase and endopeptidase work in harmony to regulate the degradation of the major globulin proteins of linseed.