The component of Carica papaya seed toxic to A-aegypti and the identification of tegupain, the enzyme that generates it

Autor(es)

Nunes, Natalia N. dos S. ^[1] ; Santana, Lucimeire A. ^[1] ; Sampaio, Misako U. ^[1] ; Lemos, Francisco J. A. ^[2] ; Oliva, Maria Luiza ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Paulo, Dept Bioquim, BR-04044020 Sao Paulo - Brazil

^[2] Univ Estadual Norte Fluminense, Biotechnol Lab, Campos Dos Goytacazes, RJ - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Chemosphere; v. 92, n. 4, p. 413-420, JUL 2013.
• Citações Web of Science: 8

Resumo

As Aedes aegypti transmits the etiologic agents of both yellow and dengue fever; vector control is considered essential to minimise their incidence. The aim of this work was to identify the component of Carica papaya seed toxic to A. aegypti, and the identification of tegupain, the enzyme that generates it. Aqueous extracts (1%, w/v) of the seed tegument and cotyledon of C. papaya are not larvicidal isolately. However, a mixture of 17 mu g mL(-1) tegument extract and 27 mu g mL(-1) cotyledon extract caused 100% larval mortality in a bioassay. The mixture was no longer larvicidal after the tegument extract was pre-treated at 100 degrees C for 10 min. The enzyme tegupain efficiently hydrolysed the substrate Z-Phe-Arg-pNan (K-m 58.8 mu M, K-cat 28020 s(-1), K-cat/K-m 5 x 10(8) M-1 s(-1)), and its activity increased with 2 mM dithiothreitol (DTT), at 37 degrees C, pH 5.0. The chelating agent EDTA did not modify the enzyme activity. Inhibition of tegupain by cystatin (K-iapp 2.43 nM), E64 (3.64 nM, 83% inhibition), and the propeptide N-terminal sequence indicate that the toxic activity is due to a novel cysteine proteinase-like enzyme, rendered active upon the hydrolysis of a cotyledon component of C. papaya seeds. (c) 2013 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 09/17058-6 - Purificação e caracterização de compostos isolados de plantas com atividade larvicida.
• Beneficiário: Natalia Neto dos Santos Nunes
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 09/53766-5 - Proteínas de origem vegetal com seletividade para inibição de enzimas de mamíferos e seu papel como agente anti-inflamatório, antitrombótico, antidiabético e antitumoral
• Beneficiário: Maria Luiza Vilela Oliva
• Modalidade de apoio: Auxílio à Pesquisa - Temático