Distribution of acidic proteases in Gramineae. Kinetics of protein degradation in wheat Triticum aestivum [cv. Giza 164] during germination

ABSTRACT

Acidic protease activity was quantitatively screened in 28 species and cultivars of Gramineae family during germination. Most cultivars of cereals and some grasses as Oryza sativa and Avena fatua, not economic plants, had high acidic protease activity and could be a potentially good starting material for preparation of proteases. Kinetics of protein degradation in Triticum aestivum [cv. Giza 164] seeds during germination was examined. The results revealed that protease activity was dramatically increased from the second day of germination and reached its maximum activity on day 10. This increase in protease activity was accompanied by a decrease in soluble protein content. Gibberellic acid [GA3] caused an obvious increase in protease activity during germination that reached a 1.8-fold increase on day 10 over the untreated seeds concomitant with high decrease of the protein content. The isoenzyme pattern of T. aestivum protease during germination showed the differences in number and relative mobility of isoenzyme bands in absence and presence of GA3. The number of isoenzymes was increased from 9 to 12 in presence of GA3. Only three isoenzymes were detected in absence and presence ofGA3. The electrophoretic pattern of protein showed that the number and intensity of bands were increased, specially on days 8 and 10 and number of low molecular weight bands also appeared from days 4 to 14 in presence of GA3