Navegando por Palavras-chave "serine proteinase"

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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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    Primary sequence determination of a Kunitz inhibitor isolated from Delonix regia seeds
    (Elsevier B.V., 2001-07-01) Pando, S. C.; Oliva, MLV; Sampaio, CAM; Di Ciero, L.; Novello, J. C.; Marangoni, S.; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Campinas (UNICAMP)
    A serine proteinase inhibitor was purified from Delonix regia seeds a Leguminosae tree of the Caesalpinioideae subfamily. the inhibitor named DrTI, inactivated trypsin and human plasma kallikrein with K-i values 2.19x10(-8) M and 5.25 nM, respectively. Its analysis by SDS-PAGE 10-20% showed that the inhibitor is a protein with a single polypeptide chain of M-r 22 h Da. the primary sequence of the inhibitor was determined by Edman degradation, thus indicating that it contained 185 amino acids and showed that it belongs to the Kunitz type family; however, its reactive site did not contain Arg or Lys at the putative reactive site (position 63, SbTI numbering) or it was displaced when compared to other Kunitz-type inhibitors. (C) 2001 Elsevier B.V. All rights reserved.
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    Purification and partial characterization of kininogenase activity from Schistosoma mansoni adult worms
    (Cambridge Univ Press, 1998-10-01) Carvalho, W. S.; Lopes, C. T.; Juliano, L.; Coelho, PMZ; Cunha-Melo, JR; Beraldo, W. T.; Pesquero, J. L.; Universidade Federal de Minas Gerais (UFMG); Universidade Federal de São Paulo (UNIFESP)
    An enzyme presenting kallikrein-like activity (designated sK1) was purified from the supernatant of Schistosoma mansoni adult worm homogenate. the enzyme cleaves bradykinin from purified rat plasma kininogen. Activity was optimal at pH 9.0 and the enzyme showed amidolytic activity, since it hydrolysed the kallikrein synthetic substrate D-Pro-Phe-Arg-p-nitroanilide. the activity of sK1 upon rat plasma kininogen was strongly inhibited by the serine proteinase inhibitors phenylmethanesulfonyl fluoride, aprotinin or soybean trypsin inhibitor, but not by ethylenediaminetetraacetic acid or sodium tetrathionate. the molecular mass of sK1, as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, was 66 kDa and the pI value, estimated by analytical chromatofocusing, was 4.2. Physical and chemical properties suggest that sK1 is a serine proteinase of the kallikrein family. Evidence is presented which suggests that sK1 is a component of the tegumental surface of the parasite and the levels of its activity in the male adult worm are approximately 21 times higher than those in the female adult worm. the intravenous injection of 3 mu g of sK1 into an anaesthetized rat induced a drastic reduction in the arterial blood pressure of the animal. This effect lasted for about 1 min, and was followed by a progressive recovery of the arterial pressure. Neither bradycardia nor cardiac arrhythmias were noticed, suggesting a peripheral vasodilation effect. the presence of sK1 on the surface of adult male worms could play an important role in the wandering capacity of coupled worms into the visceral vasculature of the host.
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    Purification and preliminary characterization of a plasma kallikrein inhibitor isolated from sea hares Aplysia dactylomela Rang, 1828
    (Elsevier B.V., 2004-02-01) Gonzalez, Y.; Araujo, M. S.; Oliva, MLV; Sampaio, CAM; Chavez, M. A.; Univ La Habana; Universidade Federal de São Paulo (UNIFESP)
    An inhibitor active against pancreatic trypsin was found in the crude extract from the sea hares Aplysia dactylomela Rang, 1828. A stronger inhibitory activity against human plasma kallikrein was detectable after treating this extract at 60 T, for 30 min. the plasma kallikrein inhibitor (AdKI) purification was achieved by acetone fractionation (80%) v/v, ion-exchange chromatography on Mono Q column and gel filtration chromatography on Superdex 75 column (FPLC system). By the latter a molecular mass of 2,900 Da was estimated. the purified inhibitor strongly inhibits human plasma kallikrein with a K-i value of 2.2 X 10(-10) M, while human plasmin and pancreatic trypsin were inhibited with K-i values of 1.8 X 10(-9) and 4.7 x 10(-9) M, respectively. Chymotrypsin, pancreatic elastase, pancreatic kallikrein and thrombin are not inhibited. the effect of AdKI on plasma kallikrein was confirmed by the prolongation of activated partial thromboplastin time, using a clotting time assay. the inhibitor did not affect prothrombin time or thrombin time. AdKi is a more specific inhibitor than other serine proteinase inhibitors from marine invertebrates. (C) 2003 Elsevier B.V. All rights reserved.
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    Trypanosoma cruzi heparin-binding proteins present a flagellar membrane localization and serine proteinase activity
    (Cambridge Univ Press, 2013-02-01) Oliveira-, F. O. R.; Alves, C. R.; Silva, F. S.; Cortes, L. M. C.; Toma, L. [UNIFESP]; Boucas, R. I. [UNIFESP]; Aguilar, T. [UNIFESP]; Nader, H. B. [UNIFESP]; Pereira, M. C. S.; Fiocruz MS; Universidade Federal de São Paulo (UNIFESP)
    Heparin-binding proteins (HBPs) play a key role in Trypanosoma cruzi-host cell interactions. HBPs recognize heparan sulfate (HS) at the host cell surface and are able to induce the cytoadherence and invasion of this parasite. Herein, we analysed the biochemical properties of the HBPs and also evaluated the expression and subcellular localization of HBPs in T. cruzi trypomastigotes. A flow cytometry analysis revealed that HBPs are highly expressed at the surface of trypomastigotes, and their peculiar localization mainly at the flagellar membrane, which is known as an important signalling domain, may enhance their binding to HS and elicit the parasite invasion. the plasmon surface resonance results demonstrated the stability of HBPs and their affinity to HS and heparin. Additionally, gelatinolytic activities of 70 kDa, 65.8 kDa and 59 kDa HBPs over a broad pH range (5.5-8.0) were revealed using a zymography assay. These proteolytic activities were sensitive to serine proteinase inhibitors, such as aprotinin and phenylmethylsulfonyl fluoride, suggesting that HBPs have the properties of trypsin-like proteinases.