Fluorogenic Substrate of Pepsin

Article abstract of DOI:10.1246/bcsj.64.1407

Fluorogenic substrates of pepsin; Dns-Ala-Phe-Trp-Val-Leu-OCH2Py and Dns-Phe-Trp-Val-Leu-OCh2Py were synthesized by a solution method.Incubation of pepsin with Dns-Ala-Phe-Trp-Val-Leu-OCH2Py resulted in specific cleavage at the Phe-Trp bond and the time-dependent increase in fluorescence intensity at 345 nm paralleling the extent of substrate hydrolysis.The optimum pH of the substrate was 3.0 and K_m and k_cat values were 8.0x10^-5 M and 0.10 s^-1, respectively.The linearity of the plot of fluorescence intensity vs. enzyme concentration was satisfactory in the range of 50 nM to 500 nM of pepsin at a substrate concentration of 50 μM.Because of its simplicity and rapidity, this method is useful for the measurement of pepsin action.In contrast, Dns-Phe-Trp-Val-Leu-OCH2Py was not cleaved by pepsin.