Denisov I G, Illarionova N G, Ponomareva R B, Samsanov G V
Biofizika. 1988 Nov-Dec;33(6):950-3.
Effect of complex formation with dextran sulfate (DS) (substitution degree 1.3, molecular mass 500 thousand) on RNAse enzymic activity. its spatial structure and conformation stability was studied. Hydrolytic activity of the enzyme in complex in inhibited already at small additions of DS, while the transferase one is changed only at a great excess of the polyelectrolyte. It has been shown by CD spectra that no notable conformation changes proceed in the enzyme during complex formation, although the enzyme turns destabilized to the denaturing effect of heat at the expense of strengthened interactions between DS and RNAse during its denaturation. Thus the inhibition of hydrolytic activity in the complex is primarily related to limitations for the formation of the enzyme-substrate complex on polyelectrolyte charged likely with the substrate, and not to the protein conformation changes.
研究了与硫酸葡聚糖（DS）（取代度1.3，分子量50万）形成复合物对核糖核酸酶酶活性、其空间结构和构象稳定性的影响。在少量添加DS时，复合物中酶的水解活性就已受到抑制，而转移酶活性仅在聚电解质大量过量时才发生变化。圆二色光谱表明，在形成复合物过程中酶没有明显的构象变化，尽管在变性过程中，由于DS与核糖核酸酶之间相互作用增强，酶对热变性作用变得不稳定。因此，复合物中水解活性的抑制主要与可能带底物电荷的聚电解质上酶-底物复合物形成受限有关，而非与蛋白质构象变化有关。
