【摘要】 为了解两种基质金属蛋白酶———成纤维细胞胶原酶I(fibroblastcollagenase 1)和基质酶I(stromelysin 1)的结构异同 ,利用荧光光谱学和高压力方法比较了这两种酶催化区的结构特性。研究发现胶原酶I的催化区基本不结合荧光探针ANS ,而基质酶I的催化区可以结合ANS ,其解离平衡常数为 2 6 .3μmol/L ,表明后者催化区表面有疏水区存在 ,进一步研究表明该疏水区可能不在活性中心。胶原酶I和基质酶I在高压力下的生物活性变化亦有所不同 :随着压力升高 ,胶原酶I水解底物的活性显著增加 ,1.8kbar时表观活性为常压下的 3倍多 ,由此估算胶原酶I的表观活化体积为 - 18.9ml/mol。基质酶I的活性则基本不随压力变化而变化 ,表明这两个酶反应的表观活化体积有很大的差异。这些结果表明 ,晶体结构十分类似的胶原酶I和基质酶I催化区在溶液中实际存在着明显差异。更多还原

【Abstract】 The catalytic domains of two matrix metalloproteinases——collagenase 1 and stromelysin 1 have been studied by means of fluorescence spectroscopy and high hydrostatic pressure. The hydrophobic fluorescence probe ANS could bind to stromelysin 1, with a dissociation constant of 26.3 μmol/L, but could not bind to collagenase 1, indicating that there exists a hydrophobic site on the surface of stromelysin 1. Further study suggests that the hydrophobic site may not be the catalytic site. The biological activity of catalytic domains of collagenase 1 and stromelysin 1 showed obvious difference under high pressure: the activity of collagenase 1 increased with elevating pressure, with an apparent activation volume of -18.9 ml/mol; however, the activity of stromelysin 1 did not change under high pressure. The results indicate that there are some obvious differences between the catalytic domain conformations of these two enzymes, though the crystal analysis indicated that they were very similar as reported before.更多还原