pepsin were measured by the increase in fluorescence. The substrate I was hydrolyzed with pepsin by hundreds times faster than the substrates II and IV. The minimal detectable pepsin concentration of the substrate I was 0.5 nM and those of the substrates II and IV were 20 nM and 50 nM (M = mol dm−3). The substrates were sufficiently soluble in acidic buffers at their optimum pH. The inhibition rates of
胃
蛋白酶的荧光底物;Dns–Ala–Ala–Phe–Trp–Val–Leu–OCH2Py (I)、Ala–Ala–Trp–Phe–Leu–NHNHDns (II) 和 Ala–Ala–Trp–Phe–NHNHDns (III) 由以下合成:一种溶液方法及其性质与 Dns-Ala-Phe-Trp-Val-Leu-OCH2Py (IV) 进行了比较。合成底物 I 和 II 在 Phe 和 Trp 残基之间被胃
蛋白酶特异性切割并增加荧光,尽管底物 III 没有被胃
蛋白酶水解。胃
蛋白酶对底物的
水解速率通过荧光的增加来测量。底物 I 被胃
蛋白酶水解的速度比底物 II 和 IV 快数百倍。底物 I 的最小可检测胃
蛋白酶浓度为 0.5 nM,底物 II 和 IV 的最低可检测胃
蛋白酶浓度为 20 nM 和 50 nM (M = mol dm-3)。底物在其最佳 pH 值下可充分溶于酸性缓冲液。胃
蛋白酶抑