Characterization and ecological implications of midgut proteolytic activity in larvalPieris rapae andTrichoplusia ni
- 1 July 1989
- journal article
- research article
- Published by Springer Nature in Journal of Chemical Ecology
- Vol. 15 (7), 2101-2113
- https://doi.org/10.1007/bf01207441
Abstract
In their larval luminal midgut fluid,Trichoplusia ni (Lepidoptera: Noctuidae) andPieris rapae (Lepidoptera: Pieridae) contain endopeptidases as their primary proteases. Neither species has detectable exopeptidase activity. Studies using enzyme-specific substrates and inhibitors demonstrate that the endopeptidases are serine proteinases (both trypsinlike and chymotrypsinlike) with histidine at the active site. Optimal pH for the tryptic and chymotryptic activity is 8.5 and 8.0, respectively, forT. ni. and 8.0 and 9.0, respectively, forP. rapae. The efficiency of proteolytic digestion (as measured by the rate of in vitro digestion of a standard protein by the midgut luminal fluid) is positively correlated with the larval dietary protein requirement and is significantly influenced by the ratios of tryptic to chymotryptic activity present in the gut lumen of these two species of Lepidoptera.Keywords
This publication has 39 references indexed in Scilit:
- Tryptic inhibitory activity in wild and cultivated crucifersPhytochemistry, 1989
- A novel mechanism of insect resistance engineered into tobaccoNature, 1987
- Plant Proteinase inhibitors: A defense against herbivorous insects?Entomologia Experimentalis et Applicata, 1986
- Presence and partial characterisation of a major proteolytic enzyme in the larval gut of Callosobruchus maculatusEntomologia Experimentalis et Applicata, 1985
- Alkaline proteases in digestive juice of the silkworm, Bombyx moriBiochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1982
- Adaptive Significance of Midgut pH in Larval LepidopteraThe American Naturalist, 1980
- Insect Proteases and PeptidasesPublished by Wiley ,1977
- Trypsin inhibitors in plantsPhytochemistry, 1973
- The inhibition of enzymes by tanninsPhytochemistry, 1965
- A MODIFIED SPECTROPHOTOMETRIC DETERMINATION OF CHYMOTRYPSIN, TRYPSIN, AND THROMBINCanadian Journal of Biochemistry and Physiology, 1959