Acid phosphatase and protease release by the insectivorous plant Drosera rotundifolia

Abstract

The leaves of the insectivorous plant Drosera rotundifolia L. produced extracellular hydrolytic enzymes in response to feeding with gelatin. Enzyme release was first detected 1 to 2 days after feeding, reached a maximum on day 4, and then gradually declined. Optimal activity of both acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) and protease enzymes was in the acidic range of pH. The acid phosphatase attacked a range of phosphorylated compounds but its p-nitrophenylphosphatase (PNPPase) and ribonucleoside triphosphatase activities were highest. It displayed relatively low phosphomonoesterase (EC 3.1.3.1, 3.1.3.2) activity. Both acid phosphatase and protease enzymes were insensitive to the sulphydryl inhibitor N-ethylmaleimide. The acid phosphatase was strongly inhibited by fluoride and orthophosphate. The nature of the apparent induction of hydrolase enzyme activity is briefly discussed.