Regulation of Phospholipase Activity in Potato Leaves by Protein Phosphorylation-dephosphorylation and Proteolytic Activation
We have recently reported that calcium and calmodulin stimulate the rate of autolysis of phospholipids in potato leaf homogenates (1). Further studies (2) revealed that a soluble phospholipase activity in potato leaves could be stimulated to the same degree (30–50%) by either calmodulin or protein kinase (+ATP). Two other plant enzymes, quinate: NAD+ oxidoreductase (3) and isofloridoside-phosphate synthase (4), have also been shown to be similarly stimulated by both calmodulin and protein phosphorylation. However, the latter enzyme was also shown to be stimulated to an even greater degree by proteolysis with trypsin or chymotrypsin (4). This study was undertaken to investigate whether the phospholipase activity in potato leaves may also respond to proteolytic activation.
KeywordsProteolytic Activation Supernatant Fraction Phospholipase Activity Potato Leave Plant Enzyme
Unable to display preview. Download preview PDF.
- 2.R. A. Moreau, Regulation of phospholipase activity in potato leaves by calmodulin and protein phosphorylation-dephosphorylation, Plant Sci., (in press).Google Scholar
- 7.G. H. DeHaas, N. M. Postema and W. Nieuwenhuizen, and L. L. M. VanDeenen, Purification and properties of an anionic zymogen of phospholipase A2 from porcine pancreas, Biochem. Biophys. Acta., 159: 118 (1968).Google Scholar