Purification of immunoglobulin and serum albumin from serum via strong anion exchange chromatography coupled with molecular exclusion chromatography

The isoelectric points of immunoglobulin (Ig) and serum albumin (SA) in animal serum are about 7.8 and 4.8, respectively. Based on their larger difference of isoelectric points, Q Sepharose-XL strong anion exchange chromatography coupled with molecular exclusion chromatography was used to purify Ig and SA simultaneously from the high immune rabbit serum. After the Q Sepharose-XL strong anion exchange column was equilibrated with 0.02 mol/L Tris-HCl buffer of pH 8.0, a 10-fold dilution sample of rabbit serum was loaded onto the column and the pH gradient elution was performed. With the low flow rate of elution of 0.3 mL/min, the high-purity Ig was obtained when the elution pH was at 6.0. Continuously eluted at pH 4.0 with the same flow rate of elution, the SA was obtained and its purity was greater than 95% after molecular exclusion chromatography through Sephadex G-75. The purified Ig and SA were demonstrated to maintain normal activities by activity analysis. The results of protein content showed that the purification recoveries of Ig and SA were over 95% and 90%, respectively. The method has the advantages of simple operation and rapidity, and the Ig and SA purified simultaneously from the animal serum could maintain normal activities.