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Type: Artigo de periódico
Title: Purification and biochemical properties of a Kunitz-type trypsin inhibitor from Entada acaciifolia (Benth.) seeds
Author: Ramalho de Oliveira, Caio Fernando
Vasconcelos, Ilka Maria
Aparicio, Ricardo
Machado Freire, Maria das Gracas
Baldasso, Paulo Aparecido
Marangoni, Sergio
Rodrigues Macedo, Maria Ligia
Abstract: A new trypsin inhibitor (EATI) was isolated from Entada acaciifolia (Benth.) seeds. EATI is a competitive inhibitor with a molecular mass of 20 kDa and an inhibition stoichiometry of 1:1 for bovine trypsin. The dissociation constant (K-i) calculated was 1.75 nmol/L, displaying a high affinity between enzyme and inhibitor. Both Native PAGE and RP-HPLC revealed that EATI is composed of four isoinhibitors that share the amino acid composition and the amino-terminal sequence homolog to Kunitz-type inhibitors. EATI is stable to denaturation by heat (up to 70 degrees C), pH (2-10), urea (8 mol/L) and its inhibitory activity was unaltered in different concentrations of DTT (up to 100 mmol/L). CD analysis revealed that EATI in reduced form underwent structural modifications associated with a decrease in thermal and pH stabilities, suggesting that their disulfide bonds are not involved in the structuring of its reactive site, but are important for maintenance of its conformational stability. This behavior makes EATI one of the few inhibitors described in the literature with high DTT resistance. (C) 2012 Elsevier Ltd. All rights reserved.
Subject: Entada acaciifolia
Circular dichroism
Kunitz-type inhibitor
Trypsin inhibitor
Editor: Elsevier
Citation: Process Biochemistry. Elsevier, v.47, n.6, p.929-935, 2012
Rights: fechado
Identifier DOI: 10.1016/j.procbio.2012.02.022
Date Issue: 2012
Appears in Collections:IB - Artigos e Outros Documentos

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