溶菌酶在疏水表面吸附的研究  

Study on lysozyme adsorption at the hydrophobic surface

作　　者：吴雅妮[1] 耿信鹏[1] 陈立成[1] 耿信笃[2] 邢建伟[3] 

机构地区：[1]西安工程科技学院环境与化学工程学院,陕西西安710048 [2]西北大学现代分离科学研究所,陕西西安710069 [3]西安工程科技学院纺织与材料学院,陕西西安710048

出　　处：《纺织高校基础科学学报》2005年第1期1-6,共6页Basic Sciences Journal of Textile Universities

基　　金：陕西省自然科学研究计划项目(2004B25);西安市科技局工业科技攻关项目(GG200270);西北大学2004年度重点科研基地开放基地资助项目.

摘　　要：采用摇床法,通过改变盐酸胍浓度和溶菌酶浓度测定不同温度下的变性溶菌酶(Lys)在疏水色谱填料PEG 600表面的吸附等温线.研究发现,25℃,35℃和45℃吸附达平衡所需时间分别为5h,4h和2h.原因可能是25℃时包覆作用显著,温度升高时,包覆作用消失,吸附容易达到平衡.改变盐酸胍浓度时,吸附量的变化与三种作用力,即去水合作用、亲合力及分子构象作用力的相对大小有关.0.8mol/LGuHCl吸附量达最大值,暗示蛋白可能发生了构象突变(至少是微扰).以吸附计量置换模型(SDM A)对溶菌酶的吸附等温线进行拟合的线性关系很好,表明SDM A适用于溶菌酶在液固界面上的吸附.SDM A热力学研究表明,变性溶菌酶折叠吸附过程中总的自由能ΔGP为负值,净吸附自由能ΔGA均比相应条件下的ΔGP的负值更大,而净解吸附自由能ΔGD均为正值.说明上述自发过程是由ΔGA作为驱动力的结果,符合吸附过程的一般规律.Adsorption isotherm of lysozyme(Lys) which originally had been denatured by guanidine hydrochloride (GuHCl) at the hydrophobic chromatography packings (end group PEG600) surface has been determined under the condition of changing the concentration of lysozyme and GuHCl under different temperatures using vibrator. It is found that the adsorption equilibrium time corresponding to 25℃,35℃ and 45℃ is 5 h, 4 h and 2 h, respectively. It may be because the phenomenon that the adsorbed Lys molecules were 'wrappedup' at 25℃ is remarkably, and that of wrapping disappears when temperature increases to 35℃ and 45℃ because the adsorption equilibrium state is easy to reach at higher temperatures. The adsorption amounts changeable with C_(GuHCl) are relative to three interactions, i.e. dehydration, adsorption affinity and molecular conformation; the adsorption maximum amount of C_(GuHCl) 0.8 mol/L implies that a mutation (or turbulence at least) of molecular conformation may occur. The fact that the good linear relationship of adsorption isotherms of Lys plotted by stoichiometric displacement model of adsorption (SDMA) exists demonstrates that SDMA is appropriate for Lys folding adsorption at the PEG600 surface. Thermodynamic study of SDMA shows that the total Gibbis free energies(ΔG_P) of Lys folding are all negative; the net adsorption free energies(ΔG_A) are all greater than the corresponding ΔG_P in negative value; and the net desorption free energies are all positive. The spontaneous processes are the result of ΔG_A as driving force, which fits the general rule of adsorption process.

关 键 词：溶菌酶 疏水填料 吸附 吸附计量置换模型(SDM-A) 热力学 

分 类 号：O643.1[理学—物理化学]