参数Z对疏水色谱中胍变蛋白质分子构象变化的表征

用计量置换参数Ｚ对疏水色谱流动相中存在盐酸胍时蛋白质分子构象变化进行了表征。除溶菌酶外，其余４种蛋白质的Ｚ值随盐酸胍浓度的增大先增大，而后减小。将盐酸胍和脲对蛋白质Ｚ值的影响进行了比较后发现，在疏水色谱中Ｚ值作为蛋白质分子构象变化表征的一个重要的结论是随变性剂浓度的增大，埋藏在蛋白质分子内部的疏水性氨基酸残基暴露到分子表面的程度逐渐增大，造成了Ｚ值随蛋白质分子构象变化程度的增大而减小。蛋白质的Ｚ值随盐酸胍及脲浓度变化的不同特点，反映了两者对蛋白质变性机理的不同。

Characterization of the Relationship Between Concentration of Guanidine Bydrochloride and Molecular Conformation of Biopolymers in Hydrophobic Interaction Chromatography by Parameter Z

The Z value of the stoichiometric displacement model for retention (SDM-R) was used to characterize the changes in the molecular conformations of proteins. Except lysozyme, the Z values of other four kinds of proteins were found to increase firstly, and then decrease with increasing concentration of guanidine hydrochloride (GuHCl) in the mo- bile phase used. After comparing the effects of various kinds of denaturants, urea, and GuHCl on the Z values of proteins, we found that the hydrophobic amino acid residues buried in the interna1 of protein molecules exposed gradually to the surfaces of the molecules with increasing concentration of the denaturant used. As a result, the Z values of proteins decrease. The different changes in Z values of proteins with the concentration of GuHCl and urea reflect different denaturation mechanisms of proteins induced by these two denaturants.