Peptide hydrolases in senescing ragi leaves

Two peptide hydrolases — one active at pH 7.0 and the other at pH 3.4 (SH-dependent) were detected in ragi (Eleusine coracana Gaertn. cv. PR 202) leaves. The absolute activities of both acid and neutral peptide hydrolases were move or less stable in attached leaves and exhibited a mild rise in excised leaves, whereas the specific activities exhibited a significant rise. Light and growth regulators were ineffective in changing the course of absolute activity whereas cytokinins stimulated specific activities of both acid and neutral peptide hydrolases. Though the rates were different, protein decline was positively correlated with the changes in activities of peptide hydrolases. Cycloheximide retarded chlorophyll and protein decline and also prevented the rise in peptide hydrolases. Peptide hydrolases thus do not have an active role in senescence.