Proteolytic enzymes in excretory-secretory products from adult Nematospiroides dubius

Excretory-secretory products (ES), collected from in vitro cultures of adult Nematospiroides dubius, were examined for proteolytic enzyme activity. ES enzymes had a pH optimum of 8.0 and their activity was sensitive to serine-proteinase inhibitors. Three SDS-resistant proteases were identified in ES at molecular weight (mol. wt) 200,000, 105,000 and 48,000 by incorporating substrates into the matrices of sodium dodecyl sulfate-polyacrylamide electrophoresis (SDS-PAGE) gels.