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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。
To understand the similarities and differences between the two matrix metalloproteases, fibroblastcollagenase 1 and stromelysin 1, the structures of these two catalytic regions were compared using fluorescence spectroscopy and high pressure methods characteristic. It was found that the catalytic region of collagenase I did not bind to the fluorescent probe ANS, whereas the catalytic region of substrate enzyme I could bind to ANS with an equilibrium dissociation constant of 26.3 μmol / L, indicating that there was hydrophobic region on the catalytic region of the latter Further studies showed that the hydrophobic region may not be active center. Changes in the biological activity of collagenase I and substrate enzyme I at high pressures are also different: with increasing pressure, the activity of collagenase I hydrolyzed substrate increased significantly, with an apparent activity at 3 kPa at 1.8 kbar The estimated apparent activation volume of collagenase I was - 18.9 ml / mol. The activity of substrate enzyme I changed little with pressure, indicating that the apparent activation volumes of these two enzyme reactions are quite different. These results indicate that there is actually a significant difference in solution between the collagenase I and substrate enzyme I catalytic regions whose crystal structure is very similar.