A trypsin inhibitor purified from Cassia leiandra seeds has insecticidal activity against Aedes aegypti

• DOI: 10.1016/j.procbio.2017.03.015
• Publication Date: 2017-03-27T22:46:31Z
• Authors: Lucas P. Dias; Jose T.A. Oliveira; Lady C.B. Rocha-B...; Daniele O.B. Sousa; Helen P.S. Costa; Nadine M.S. Araujo; Ana F.U. Carvalho; Pedro M.S. Tabosa; Ana C.O. Monteiro...; Marina D.P. Lobo; Frederico B.M.B. ...; Bruno A.M. Rocha; José L.S. Lopes; Leila M. Beltramini; Ilka M. Vasconcelos
• Keywords: Trypsin inhibitor

A trypsin inhibitor from Cassia leiandra seeds, named ClTI, was purified, characterized, and its insecticidal activity against Aedes aegypti evaluated. ClTI purified by DEAE-Cellulose trypsin-Sepharose 4B chromatography, with a 15.5-fold purification 2.4% yield. is composed of 19,484 Da polypeptide chain as revealed mass spectrometry, it not glycoprotein, amino acid sequence similar to other Kunitz-type inhibitors, comprises 35% β-sheets, 14% β-turns, 50% disordered secondary structures. an uncompetitive bovine (IC50 33.81 × 10−8 M, Ki 6.25 M) stable over broad range pHs (2.2–10.0) temperatures (30–70 °C), but dithiothreitol led partial loss the inhibitory activity. at 4.65 10−6 reduced in Ae. midgut proteases. also promoted acute toxicity on 3rd instar larvae aegypti, LC50 2.28 10−2 M. Moreover, caused 24-h delay development 44% mortality after ten days exposure. Altogether, these results suggest that has potential natural compound control vector several infection diseases.