Synthesis of Carbobenzoxy-alanyl-thiaarginine (thialysine) benzyl ester and Kinetic Studies with Trypsin

摘要

Carbobenzoxy-alanyl-thiaarginine benzyl ester and carbobenzoxy-alanyl-thialysine benzyl ester were synthesized in solution. Kinetic studies were carried out using three different analytical methods, semi-classical method, progress curve analysis and competitive spectrophotometry. In competitive spectrophotometry, carbobenzoxy-valyl-glycyl-arginyl-p-nitroaniline was used as a detector. Kinetic constants such as Km and Vmax measured by competitive spectrophotometry are almost the same as those values measured by semi-classical method. Colorimetric Ellman`s assays showed the thio-peptido mimetics to be a suitable substrates for trypsin. Kinetic studies with trypsin gave Km of 2.33 mM and kcat of 1.50 x 105 min-1 for carboxy-alanyl-thiaarginine benzyl ester and Km of 3.41 x 10-3 mM and kcat of 520 x 102 min-1 for carbobenzoxy-alanyl-thialysine benzyl ester, respectively. Kinetic constants (Km=2.04 x 10-2 mM, Kcat=4.42 x 103 min-1) for natural substrate, carbobenzoxy-alanyl-lysine benzyl ester, were also evaluated by competitive spectrophotometry in order to compare the mode of binding on trypsin.