COMPARISON BETWEEN GUANDINUM-INDUCED ACTIVTTY AND CONFORMATION CHANGES OF STAPHYLOCOCCAL NUCLEASE AND ITS ANALOGUE
金黄色葡萄球菌核酸酶及其类似物盐酸胍变性的活力与构象变化的比较

There were no difference in unfolding or refolding conformational tansition curves and specific activity between staphylococcal nuclease(SNase)and its analogue (SNaseR).Their unfolding and refolding conformational transition curves were overlapped, but their reactivition were lagged of inactivition. Low concentration of guanidinium shoal an activition of 20%,and 0.125mol/L sodium chloride showed an activition of nearly 100%.Compared the intrinsic fluorescence of tryptophan with tyrosine of the tertiary complex, formed by SNaseR,deoxythymidine-3'-5'-diphosphate (pdTp) and Ca2+, during equilibrium unfolding induced by guaniddrium, it was found that the conformation of active site of SNaseR was changed prior tO its conformational structare as a Whole, resulting in the enhance of the dissociation constant, Kd, between SNaseR and its competitive inhibitor pdTp.