Henes J B, Mattis J A, Fruton J S
Proc Natl Acad Sci U S A. 1979 Mar;76(3):1131-4. doi: 10.1073/pnas.76.3.1131.
Fluorescence studies have been performed on the interaction of papain with active-site-directed inhibitors of the type mansyl-(Gly)n-Phe-glycinal, where n = 0, 1, 2. It has been found that whereas the mansyl [6-(N-methylantilino)-2-naphthalene sulfonyl] fluorescence of mansyl-Phe-glycinal is greatly enhanced, that of the two longer mansyl compounds is not, although all three are equally effective as inhibitors of papain action. Measurements of fluorescence polarization and rotational relaxation time support the conclusion that the fluorescent probe group of the two longer mansyl compounds protrudes into the solvent to a greater degree than that of mansyl-Phe-glycinal. Considerable energy transfer from papain tryptophan to the mansyl group is evident for all three inhibitors, however, although it is most marked with mansyl-Phe-glycinal. Stopped-flow fluorescence measurements have shown that, after initial rapid interaction, the first-order conformational changes in the active-site region of papain in the complex with mansyl-Phe-glycinal are approximately 1/10(4) those observed with comparable mansyl oligopeptide substrates, and approximately 1/10(2) those with acetyl-Phe-glycinal.
已对木瓜蛋白酶与曼西尔-（甘氨酸）n-苯丙氨酸甘氨醛型活性位点导向抑制剂的相互作用进行了荧光研究，其中n = 0、1、2。已发现，虽然曼西尔-苯丙氨酸甘氨醛的曼西尔[6-（N-甲基抗胰蛋白酶）-2-萘磺酰基]荧光大大增强，但另外两种较长的曼西尔化合物的荧光并未增强，尽管这三种化合物作为木瓜蛋白酶作用的抑制剂效果相同。荧光偏振和旋转弛豫时间的测量结果支持这样的结论：两种较长的曼西尔化合物的荧光探针基团比曼西尔-苯丙氨酸甘氨醛的荧光探针基团更深入地伸入溶剂中。然而，对于所有三种抑制剂，从木瓜蛋白酶色氨酸到曼西尔基团都有明显的能量转移，尽管在曼西尔-苯丙氨酸甘氨醛中最为明显。停流荧光测量表明，在最初的快速相互作用之后，与曼西尔-苯丙氨酸甘氨醛形成复合物的木瓜蛋白酶活性位点区域的一级构象变化约为与可比的曼西尔寡肽底物观察到的变化的1/10(4)，约为与乙酰基-苯丙氨酸甘氨醛观察到的变化的1/10(2)。
