CHARACTERIZATION AND PARTIAL-PURIFICATION OF GUT PROTEINASES OF SPODOPTERA-EXIGUA HUBNER (LEPIDOPTERA, NOCTUIDAE)

Proteolytic activity present in the luminal contents of larval guts of the beet army worm, Spodoptera exigua (Hubner), was characterized, Se paration of gut proteins by SDS-PAGE and subsequent incubation with pr oteinase substrates visualized six separate activities, with apparent molecular masses that ranged from 29 to 110 kDa, Preincubation of the gel with specific low molecular weight inhibitors revealed the specifi cities of the separated proteinase activities, Five activity bands beh aved as serine proteinases, but a sixth band, P31, responsible for 21% of total proteinase activity was susceptible to cysteine proteinase i nhibitors, P31, P35, and P45 were subsequently partly purified by anio n exchange chromatography and further characterized with specific inhi bitors and substrates.