Separation of Proteins by a Liquid Membrane with Reverse Micelles

研究了溶菌酶(L)、核糖核酸酶A(R)和α-糜蛋白酶在含气溶胶-OT的有机相液-液萃取蛋白质的性能。当蛋白质带正电和低离子强度时，这些蛋白质在低于其等电点的反胶束(Rm)中被最显著地提取。用两种效应解释了分布平衡：带电蛋白质和AOT头基之间的静电相互作用，以及由于RM的水池而产生的尺寸排斥效应。增溶到表面活性剂溶液中的水量与盐的浓度和AOT的浓度成正比。利用搅拌槽研究了溶菌酶在水相和RM溶液之间的传质速率。在pH为4-9.2的范围内，蛋白质从水相向Rm相的正向转移发生；该速度受蛋白质通过水边界膜的扩散控制。从Rm到水相的反向转移发生在11以上。与正向转移不同，这个过程是由蛋白质从RMS释放的界面过程控制的。对液膜法分离L和R进行了进一步的研究。结果表明，L的分离因子可达954。这表明含有RMS的液膜在从水溶液中分离和浓缩蛋白质方面具有潜在的应用前景。此外，还研究了有机相中碘在大孔树脂的本体溶液和水池中的分配、溶菌酶在大孔树脂提取过程中的变性以及用大孔树脂从猪胰腺提取液中分离纯化胰酶。

Liquid-liquid extraction of proteins into an organic phase containing Aerosol-OT (AOT) in isooctane was studied for lysozyme (L), ribonuclease-A (R) and alpha-chymotrypsin. These proteins are most significantly extracted in the reverse micelles (RM) below their isoelectric points, when positively charged and at low ionic strength. The distribution equilibria were explained in terms of two effects : an electrostatic interaction between the charged protein and AOT headgroups, and size exclusion effect due to water pool of the RM. The amount of water solubilized into the surfactant solution was corredated with both concentrations of the salt and AOT. It was found that the RM solution saturated with proteins has a limiting content which depends only on the water content of the organic phase.The rate of mass transfer in the extraction of lysozyme between an aqueous phase and the RM solution was studied using a stirred cell. Forward transfer of the protein from the aqueous to the RM phase occurs in the pH range 4-9.2 ; the rate was found to be controlled by the diffusion of the protein through the aqueous boundary film. Backward transfer from the RM to the aqueous phase occurs at the values above 11. In contrast to the forward transfer, this process is controlled by the interfacial process of protein release from the RMs. Further study was made on the separation of L and R by use of a liquid membrane cell. It was found that the separation factor of L can attain to 954. This suggests that liquid membranes containing the RMs have a potential application for the separation and concentration of proteins from aqueous solutions. In addition, studies were made on the distribution of iodine between the bulk solution and water pool of the RM in the organic phase, the denaturation of lysozyme during extraction by the RM, and the purification of trypsin from an extract of porcine pancreas by use of the RMs.