Experimental and in silico studies on three hydrophobic charge-induction adsorbents for porcine immunoglobulin purification

• Published in: Chinese journal of chemical engineering 2016-01, Vol.24 (1), p.151-157
• Main Authors: Zhang, Qilei, Zhuang, Tiantian, Tong, Hongfei, Wang, Hongyin, Lin, Dongqiang, Yao, Shanjing
• Format: Article
• Language: English
• Subjects: 2-巯基苯并咪唑; Hydrophobic charge-induction chromatography; Molecular simulation; Porcine immunoglobulin; Step elution; 免疫球蛋白; 吸附剂; 猪血; 电荷; 疏水; 纯化; 诱导
• ISSN: 1004-9541; 2210-321X
• DOI: 10.1016/j.cjche.2015.06.019

Three hydrophobic charge-induction adsorbents with functional ligands of 4-mercapto-ethyl-pyridine, 2-mercapto-methyl-imidazole or 2-mercapto-benzimidazole were evaluated in the purification of porcine immunoglobulin from porcine blood. Adsorption isotherms were studied under different pH conditions. The adsorbent with 2-mercapto-methyl-imidazole as the ligand showed reasonable adsorption capacity（43.60 mg·g~（-1）gel）with great selectivity and it also showed the best elution performance in chromatographic studies. A multi-pH step elution process was proposed for the 2-mercapto-methyl-imidazole adsorbent, and the results showed that high immunoglobulin purity（94.3%） and a yield of 9.8 mg·（ml plasma）~（-1） could be achieved under the optimal condition of loading（pH 5.0）–pre-elution（pH 7.0）–elution（pH 3.8）. Moreover, molecular simulation was employed to help in analyzing the binding mechanism between the ligands and immunoglobulin, and the results showed that both 2-mercapto-benzimidazole and 2-mercapto-methyl-imidazole ligands were docked on the same pocket（around TYR319 and LEU309） of the Fc fragment of immunoglobulin, with 2-mercaptobenzimidazole showing stronger binding interactions.