Gut Luminal Digestive Proteinases of Adult Lady Beetle, Harmonia axyridis (Coccinellidae: Coleoptera), Fed an Artificial Diet

초록

The adult lady beetle, Harmonia axyridis Pallas has several proteinases in gut luminal digestive juices. Cysteine proteinases were a dominant class of the juice's proteinases and minor proteinases, if present, such as metallo proteinases, aspartic proteinases and serine proteinases, will be small in amount. Among the various chemical proteinase inhibitors (PIs) tested spectrophotometrically, the cysteine proteinase inhibitors of E-64, antipain and leupeptin inhibited most of the proteinase activities of the juices even at the micromolar concentrations. The maximum enzyme activities were observed at pH 6.0 at 45°C. The gut juice's proteinases could be separated into 2 groups, a fast moving group and a slow moving one, on both native- and SDS-PAGE. Each group was composed of several bands. Electrophoresis results suggested also that cysteine proteinases were major proteolytic enzymes of the digestive juices in the adult lady beetle. © 2002 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society.

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