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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Purifica??o, caracteriza??o e atividade bioinseticida de um inibidor de tripsina de sementes de Crotalaria pallida

Gomes, Carlos Eduardo Maia 20 December 2004 (has links)
Made available in DSpace on 2014-12-17T14:03:27Z (GMT). No. of bitstreams: 1 CarlosEMG.pdf: 434119 bytes, checksum: cffd1dddf77ec049b23dadc1bfa89773 (MD5) Previous issue date: 2004-12-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / A proteinaceous trypsin inhibitor was purified from Crotalaria pallida seeds by ammonium sulphate fractionation, affinity chromatography on immobilized Trypsin-Sepharose and TCA precipitation. The trypsin inhibitor, named ITC, had Mr of 32.5 kDa by SDS-PAGE and was composed by two subunits with 27.7 and 5.6 kDa linked by disulphide bridges, a typical characteristic of Kunitz-Inhibitor family. ITC was stable until 50?C, and at 100?C its residual activity was of about 60%. Also, ITC was stable at pHs 2 to 12. The inhibition of trypsin by ITC was non-competitive, with a Ki of 8,8 x 10-7M. ITC inhibits weakly other serine proteinases such as chymotrypsin and elastase. The inhibition of papain (44% of inhibition), a cysteine proteinase was an indicative of the bi-functionality of ITC. In vitro assays against digestive proteinases from several Lepdoptera, Diptera and Coleoptera pests were made. ITC inhibited in 100% digestive enzymes of Ceratitis capitata (fruit fly), Spodoptera frugiperda and Alabama argillacea, the last one being a cotton pest. It also inhibited in 74.4% Callosobruchus maculatus (bean weevil) digestive enzymes, a Coleoptera pest. ITC, when added in artificial diet models, affected weakly the development of C. capitata larvae and it had a WD50 of 2.65% to C. maculatus larvae / Um inibidor de proteinase foi isolado de sementes de Crotalaria pallida por fracionamento com sulfato de am?nio, cromatografia de afinidade em Sepharose com tripsina acoplada e precipita??o com ?cido tricloroac?tico (TCA). O inibidor de tripsina, denominado ITC, possui massa molecular de 32,5 kDa determinada por SDS-PAGE e ? composto por duas subunidades, uma de 25,7 e outra de 5,6 kDa, ligadas por pontes dissulfeto; uma caracter?stica t?pica da fam?lia de inibidores de Kunitz. ITC foi est?vel at? 50?C e a 100?C sua atividade residual foi cerca de 60%. ITC tamb?m foi est?vel em valores de pHs variando de 2 a 12. A inibi??o da tripsina por ITC ? do tipo n?o-competitivo, com um Ki de 8,8 x 10-7M. ITC inibe fracamente outras proteinases ser?nicas como quimotripsina e elastase. A inibi??o da papa?na (44%), uma proteinase ciste?nica, foi indicativa da bifuncionalidade de ITC. Ensaios in vitro contra proteinases digestivas de v?rios insetos praga das ordens Lepidoptera, Diptera e Coleoptera foram realizados. ITC inibiu em cerca de 100% enzimas digestivas de Ceratitis capitata (mosca-das-frutas), Spodoptera frugiperda (lagarta do cartucho do algod?o), e Alabama argillacea (curuquer? do algod?o). ITC tamb?m inibiu em 74,4% enzimas digestivas de Callosobruchus maculatus (broca do feij?o) uma praga da ordem Coleoptera. ITC, quando adicionado a dietas artificiais, afetou fracamente o desenvolvimento de larvas de C. capitata e teve um WD50 de 2,65% contra larvas de C. maculatus

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