Difference in Digestive Proteolysis in the Stored Maize Beetles: Sitophilus zeamais (Coleoptera: Curculionidae) and Prostephanus truncatus (Coleoptera: Bostrichidae)
| Autor: | N. M. R. Thie, Jon G. Houseman |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Journal of Economic Entomology. 86:1049-1054 |
| ISSN: | 1938-291X 0022-0493 |
| DOI: | 10.1093/jee/86.4.1049 |
| Popis: | Digestive proteinases in two maize feeding, stored-product insects, Sitophilus zeamais Motschulsky and Prostephanus truncates (Horn), were identified by determining the pH for maximal hydrolysis of synthetic protease substrates and the effects of potential protease activators and inhibitors. A thiol-activated cysteine proteinase was identified in S. zeamais by Bz-Arg-NHNa (benzoyl-DL-arginine- β -naphthylamide) hydrolysis with maximal activity at pH 5.5. Substrate hydrolysis was activated by thiol compounds, inhibited by iodoacetamide, and was not affected by either E64 aprotinin or soy bean inhibitor. Bz-Arg-Np (benzoyl-DL-arginine- p -nitroanilide) was not hydrolyzed by S. zeamais . Trypsin was identified in P. truncates by maximal hydrolysis of Bz-Arg-NHNa and Bz-Arg-Np at pH 9.0 and 8.5, respectively. Hydrolysis of both substrates was inhibited by aprotinin, soy bean inhibitor, and tosyl-L-lysine chloromethyl ketone and was not affected by either E64 or iodoacetamide. Chymotrypsin was identified in both insects by the hydrolysis of Bz-Tyr-OEt (benzoyl-L-tyrosine ethyl ester); maximal activity occurred at pH 7.5 in S. zeamais and at pH 8.5 in P. truncates . Substrate hydrolysis was inhibited by soy bean inhibitor, aprotinin, and tosyl-L-phenylalanine-chloromethyl ketone. |
| Databáze: | OpenAIRE |
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