The alkaline proteases of <i>Argiope</i> and their possible role in web digestion

Abstract

Abstract The digestive fluid of Argiope was assayed for its proteolytic activity with selected natural and synthetic substrates. Peak proteolytic activity was observed at pH 7.8. This was coincident with the pH of the digestive fluid. Elastolytic and weak chymotryptic activities were detected. Limited activity toward collagen was also observed. Activity toward substrates for trypsin, leucine aminopeptidase and carpboxypeptidase A and B was absent. Evidence demonstrating the in vitro digestion of web fibroin was obtained. The viscid spiral was susceptible to a variety of proteases; the radial fibers to the spider enzyme alone. Of a series of inhibitors studied, EDTA had the greatest effect upon the spider proteases. This effect was temperature dependent.