Navegando por Palavras-chave "plant inhibitor"

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    Action of Bauhinia bauhinioides synthetic peptides on serine proteinases
    (Elsevier B.V., 2003-11-07) Cagliari, C. I.; De Caroli, F. P.; Nakahata, A. M.; Araujo, M. S.; Nakaie, C. R.; Sampaio, M. U.; Sampaio, CAM; Oliva, MLV; Universidade Federal de São Paulo (UNIFESP)
    The kallikrein inhibitor found in Bauhinia bauhinioides seeds (BbKI) differs from classical Kunitz plant inhibitors in the lack of disulfide bridges in its structure [Biochim. Biophys. Acta 1477 (2000) 64-74]. in this study, we examined whether structural properties may be involved in inhibitory specificity and, if so, whether those properties might be useful tools in designing compounds that interfere with enzyme activity. Peptides structurally related to the BbKI (RPGLPVRFESPLRINIIKE-NH2) reactive site were synthesized by solid-phase method and assayed for serine proteinase activity. the peptides RPGLPVRFESPLRINIIKE-NH2, RPGLPVRFESPL-NH2, and GLPVRFES-NH2 were efficient tissue kallikrein inhibitors, with I-50 values of 0.54 muM, 0.87 muM, and 0.5 mM, respectively. the lasting inhibitory effect was observed in incubation periods of up to 120 min. None of the studied peptides interfere with the activity of thrombin, factor Xa or trypsin, although the native protein BbKI is a potent trypsin inhibitor. (C) 2003 Elsevier Inc. All rights reserved.
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    Conformational and biological properties of Bauhinia bauhinioides kallikrein inhibitor fragments with bradykinin-like activities
    (Wiley-Blackwell, 2015-06-01) Alves, Flavio Lopes [UNIFESP]; Oliva, Maria Luiza Vilela [UNIFESP]; Miranda, Antonio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Proteinase inhibitors extracted form medicinal plants are an interesting source of new drugs. Modifications in the structure of some of this kind of macromolecules could also lead to compounds of interesting biological properties. in this work, we synthesized and tested one fragment containing the reactive site of the Bauhinia bauhinioides kallikrein inhibitor (BbKI), denoted BbKI(51-62), and a related analog (P-2) in which a proline residue was inserted in order to mimic the N-terminal region of the bradykinin molecule. the related retro-inverso counterparts Ri-BbKI(51-62) and Ri-P-2 were also included. the ability of these peptides to induce contraction of stomach fundus isolated from mouse was evaluated as well as their capability to induce calcium release from a cell culture of smooth muscle from guinea pig ileum. the conformational properties of the peptides were evaluated by circular dichroism and their resistance to enzymatic degradation by exposure to human blood plasma. Our results show that neither the parent BbKI(51-62) nor its Ri-BbKI(51-62) analog exhibit bradykinin-like activity, although the retro-inverso isomer was resistant to blood plasma degradation. On the other hand, the peptides P-2 and Ri-P-2 presented contractile activities on gastric smooth muscle from stomach fundus possibly by acting via B-2 receptor. Both compounds also induce calcium release from guinea pig ileum muscle cells in a manner similar to bradykinin. Moreover, both compounds also inhibited porcine pancreatic kallikrein. However, conformational analysis did not reveal any direct correlation between structure and biological effects. Copyright (c) 2015 European Peptide Society and John Wiley & Sons, Ltd.
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    Inhibitory selectivity of canecystatin: a recombinant cysteine peptidase inhibitor from sugarcane
    (Elsevier B.V., 2004-08-06) Oliva, MLV; Carmona, A. K.; Andrade, S. S.; Cotrin, S. S.; Soares-Costa, A.; Henrique-Silva, F.; Universidade Federal de São Paulo (UNIFESP); Universidade Federal de São Carlos (UFSCar)
    The cDNA of a cystein peptidase inhibitor was isolated from sugarcane and expressed in Escherichia coli. the protein, named canecystatin, has previously been shown to exert antifungal activity on the filamentous fungus Trichoderma reesei. Herein, the inhibitory specificity of canecystatin was further characterized. It inhibits the cysteine peptidases from plant source papain (K-i = 3.3 nM) and baupain (K-i = 2.1 x 10(-8) M), but no inhibitory effect was observed on ficin or bromelain. Canecystatin also inhibits lysosomal cysteine peptidases such as human cathepsin B (K-i = 125 nM), cathepsin K (K-i = 0.76 nM), cathepsin L (K-i = 0.6 nM), and cathepsin V (K-i = 1.0 nM), but not the aspartyl peptidase cathepsin D. the activity of serine peptidases such as trypsin, chymotrypsin, pancreatic, and neutrophil elastases, and human plasma kallikrein is not affected by the inhibitor, nor is the activity of the metallopeptidases angiotensin converting enzyme and neutral endopeptidase. This is the first report of inhibitory activity of a sugarcane cystatin on cysteine peptidases. (C) 2004 Elsevier Inc. All rights reserved.