Interest in producing large quantities of plasmid DNA has recently increased as a result of the rapid evolution of gene therapy and DNA vaccines. Hydrophobic chromatography is a popular technique in the downstream processing of plasmid DNA. However, the low capacity and the high mass transfer resistance of most commercially available packings for bio-macromolecules limit their application in a large-scale process. In this work, a hydrophobic absorbent with wide pores was synthesized by the solid porogenic method. Analyses by scanning electron microscopy and mercury intrusion porosimetry revealed that the matrix contained two families of pores, i.e., micropores smaller than 100 nm and superpores of 500-7300 nm. The superpores provided not only convective flow channels for the mobile phase, but also a large surface for biomolecules binding. So the chromatographic process can be operated at high flow rate with high column efficiency and low backpressure as identified on a 2-mL column (5mm i.d., 2cm length). With a loading up to 2.6 mg of 5.4 kb plasmid (pcDNA3) in 8mL feedstock and operated at a flow rate as high as 20 cm/min, nearly 100% of plasmid was recovered with a purity of 100%. The results indicate that the hydrophobic medium is promising for high-speed purification of plasmid DNA.

研究了多种添加剂促进变性还原溶菌酶复性的作用。考察了添加剂浓度及变性剂盐酸胍浓度对复性收率的影响。结果表明，精氨酸、乙酰胺、丙酮、硫脲及甘油均能有效促进变性溶菌酶复性，并且存在最佳的添加剂浓度使变性溶菌酶的复性收率最大。在促进复性中，乙酰胺等结构类似物与盐酸胍具有相同作用，因此，在降低复性液中盐酸胍浓度的同时，适当提高乙酰胺浓度即可获得较高的复性收率。当盐酸胍浓度为0.2mol/L时，复性收率达到90%时的乙酰胺浓度为2mol/L，但降低盐酸胍浓度至0.06mol/L时，达到相同变性收率的乙酰胺浓度需要4mol/L。甘油与盐酸胍存在着协同作用，在一定浓度的盐酸胍存在下，添加适量的甘油能获得较高的复性收率。

研究了流加操作与稀释添加耦合辅助高浓度变性还原溶菌酶的复性，建立了相关的过程动力学模型。利用三态复性的过程模型对实验数据进行了拟合，获得了较好的拟合效果。利用模型分析了复性过程的动力学特性，结果表明，两者耦合可在较低的盐酸胍浓度（ mol·L-1）存在下使较高浓度的（5mg·ml-1）变性溶菌酶获得80%以上的复性收率；并且发现添加剂乙酰胺的辅助复性作用与盐酸胍相同，降低盐酸胍浓度，适当提高乙酰胺浓度即可使聚集体生成速率常数最小，酶的复性收率最大；但甘油与盐酸胍具有协同作用，只有在适当的盐酸胍浓度下添加甘油才可获得理想的复性效果。

A heptapeptide phage display library was screened with insulin to find its ligands for affinity chromatography. The peptide was synthesized and coupled to EAH Sepharose 4B (5.4umol mL-1 bed). Then, insulin chromatography was carried out with mobile phases of different pH values and by the addition of urea and ethylene glycol. It was found that electrostatic interactions were predominant for the affinity binding, and hydrogen bonding might also contribute somewhat to the affinity. Finally, frontal analysis was performed and the dynamic binding capacity of the affinity column for insulin at 50% breakthrough was estimated at 60.6mg mL-1 bed, which was about two times higher than the theoretical binding capacity of the monomeric insulin. The result suggests that insulin was bound in dimer state in a stoichiometric relationship with the coupled peptide, indicating the high binding efficiency of the peptide ligand for insulin.

The refolding kinetic behavior of denatured-reduced lysozyme in the presence of folding aids (acetamide, acetone, thiourea, l-arginine or glycerol) was studied utilizing a simplified model describing the competition between first-order folding reaction and third-order aggregation. It was found that the protein folding aids could be categorized into two groups. One of them at proper concentrations, such as acetamide, acetone, thiourea and l-arginine, stabilized unfolded protein or folding intermediates. In the presence of these additives, the folding rate decreased with increasing their concentration, and there existed a concentration where the aggregation rate constant was minimized. So, there was an optimum concentration for the folding aids to produce a high yield. The other group was protein stabilizers such as glycerol. In the presence of this kind of folding aids, both the refolding rate and yield were enhanced by increasing their concentration to a proper value. Moreover, their effect on improving protein refolding was additive to those of the first group. So the cooperative application of the two kinds of folding aids could result in favorable refolding rate and yield of protein.