Senescence-related serine protease in parsley

During leaf senescence protein degradation is enhanced. In order to obtain information on the enzymes involved in this process, a study was initiated to identify and characterize proteases whose activity is elevated in artifi cially senescing parsley leaves. A 70-kDa serine protease (EC 3.4.21) was i dentified by an activity gel assay. This protease activity, which is low in young leaves, was found to increase considerably in parallel to the advanc e of senescence and the reduction in the protein content of the leaves. A h igh correlation between the progress of senescence and the increase in the activity of the 70 kDa serine protease was demonstrated. Treatments with CO 2 or gibberellic acid, which retard senescence, reduced the protease's acti vity, whereas acceleration of senescence with ethylene enhanced it. (C) 199 8 Elsevier Science Ltd. All rights reserved.