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| Sousa,M.O.; Miranda,T.L.S.; Costa,E.B.; Bittar,E.R.; Santoro,M.M.; Figueiredo,A.F.S.. |
| Hydrolysis of D-valyl-L-leucyl-L-arginine p-nitroanilide (7.5-90.0 µM) by human tissue kallikrein (hK1) (4.58-5.27 nM) at pH 9.0 and 37ºC was studied in the absence and in the presence of increasing concentrations of 4-aminobenzamidine (96-576 µM), benzamidine (1.27-7.62 mM), 4-nitroaniline (16.5-66 µM) and aniline (20-50 mM). The kinetic parameters determined in the absence of inhibitors were: Km = 12.0 ± 0.8 µM and k cat = 48.4 ± 1.0 min-1. The data indicate that the inhibition of hK1 by 4-aminobenzamidine and benzamidine is linear competitive, while the inhibition by 4-nitroaniline and aniline is linear mixed, with the inhibitor being able to bind both to the free enzyme with a dissociation constant Ki yielding an EI complex, and to the ES complex with... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Kinetics of human tissue kallikrein inhibition; Tissue kallikrein; 4-nitroaniline; Aniline; Benzamidine; 4-aminobenzamidine; Enzyme inhibition. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000100004 |
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| Pereira,M.T.; Silva-Alves,J.M.; Martins-José,A.; Lopes,J.C.D.; Santoro,M.M.. |
| Serine-proteases are involved in vital processes in virtually all species. They are important targets for researchers studying the relationships between protein structure and activity, for the rational design of new pharmaceuticals. Trypsin was used as a model to assess a possible differential contribution of hydration water to the binding of two synthetic inhibitors. Thermodynamic parameters for the association of bovine ß-trypsin (homogeneous material, observed 23,294.4 ± 0.2 Da, theoretical 23,292.5 Da) with the inhibitors benzamidine and berenil at pH 8.0, 25ºC and with 25 mM CaCl2, were determined using isothermal titration calorimetry and the osmotic stress method. The association constant for berenil was about 12 times higher compared to the one for... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Benzamidine; Berenil; Calorimetry; Protein modeling; Trypsin; Osmotic stress. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2005001100005 |
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| Schneedorf,J.M.; Santoro,M.M.; Mares-Guia,M.. |
| Textile dyes bind to proteins leading to selective co-precipitation of a complex involving one protein molecule and more than one dye molecule of opposite charge in acid solutions, in a process of reversible denaturation that can be utilized for protein fractionation. In order to understand what occurs before the co-precipitation, a kinetic study using bovine ß-trypsin and sodium flavianate was carried out based on reaction progress curve techniques. The experiments were carried out using <FONT FACE="Symbol">a</font>-CBZ-L-Lys-p-nitrophenyl ester as substrate which was added to 50 mM sodium citrate buffer, pH 3.0, containing varying concentrations of ß-trypsin and dye. The reaction was recorded spectrophotometrically at 340 nm for 30 min, and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Flavianic acid; Tripsin inhibition; Textile dyes. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000900001 |
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