Rapid high-performance liquid chromatographic quantification of recombinant human antithrombin III during production and purification

Efficient single step chromatographic purification of recombinant human antithrombin (rhAT) from Saccharomyces cerevisiae

Antithrombin (AT) is a glycoprotein that inactivates the several physiological target enzymes of coagulation system. The effect of purification strategies plays a crucial role in getting maximum recovery of yield, purity and biological activity of recombinant human antithrombin (rhAT). In the present work, the task of purifying rhAT from Saccharomyces cerevisiae BY4741 has been carried out using two different approaches such as cross flow filtration (CFF) system and chromatography methods. In the first approach, the protein was concentrated and partially purified through CFF to achieve maximum recovery yield and purity of 87 and 94 %, respectively. In the second approach, purification involved a single step chromatography with various types of ion exchange and size exclusion resins to analyze the maximum rhAT recovery yield and purity. From the experimental results, it has been observed that the size exclusion chromatography (SEC) technique with Superose 12 matrix was suitable for the purification of rhAT and achieved the maximum recovery yield and purity of 51 and 97 %, respectively. Further, to acquire a high recovery yield and purity of rhAT, the effect of various chromatographic conditions such as mobile phase, mobile phase pH, flow rate, sample volume and sample concentration were also investigated. Under the optimal chromatographic conditions, rhAT was significantly recovered and purified in a single step with maximum recovery yield, purity and biological activity of 67, 99 % and 410 IU/L, respectively. Based on these investigations, it was concluded that SEC with Superose 12 matrix was a more suitable and a potential method for the purification of rhAT.

Production of recombinant human antithrombin III on 20-L bioreactor scale: correlation of supernatant neuraminidase activity, desialylation, and decrease of biological activity of recombinant glycoprotein

Chinese hamster ovary (CHO) cells producing the recombinant glycoprotein human antithrombin III (rhAT III) were batch cultivated in a 20-L bioreactor for 13 days. Neuraminidase activity in cell-free supernatant was monitored during cultivation and free sialic acid was determined by HPLC. Neu5Acalpha(2-->3)Gal-specific Maackia amurensis and Galbeta(1-->4)GlcNAc-specific Datura stramonium agglutinin were used for determination of sialylated and desialylated rhAT III, respectively. A commercial test kit was used for evaluation of functional rhAT III activity. Supernatant neuraminidase as well as lactate dehydrogenase activity increased significantly during batch growth. The enhanced number of dead cells correlated with increased neuraminidase activity, which seemed to be principally due to cell lysis, resulting in release of cytosolic neuraminidase. Loss of terminally alpha(2-->3) linked sialic acids of the oligosaccharide portions of rhAT III, analyzed in lectin-based Western blot and lectin-adsorbent assays, correlated with a decrease of activity of rhAT III produced throughout long-term batch cultivation. Thus, structural oligosaccharide integrity as well as the functional activity of recombinant glycoprotein depend on the viability and mortality of the bioreactor culture, and batches with a high number of viable cells are required to guarantee production of glycoproteins with maximum biological activity. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 441-448, 1997.

Recovery of antithrombin III from milk by expanded bed chromatography

In the present work, a new method of purification for antithrombin was developed using an expanded bed chromatography technique. Milk fat was removed by centrifugation and caseins were precipitated selectively by addition of zinc chloride. Crude skim milk was then directly fed to an expanded bed column containing the ion-exchange matrix. The use of a cation-exchanger (P-11) resulted in 100% adsorption and 13% recovery whereas the use of an anion-exchanger (DE-52) resulted in 100% adsorption and 84% recovery and up to five-fold purification of antithrombin. The buffer, 25 mM Tris-HCl pH 8.0; the eluting agent, 2 M (NH4)2SO4; and 100% expansion of settled bed were determined to be the optimum conditions for the purification of antithrombin by ion-exchange expanded bed chromatography. A comparison of column diameters revealed that the elution yields increase by two-fold while the column diameter increases from 1 to 2.5 cm. However, antithrombin III was concentrated to a higher degree by using the column with an internal diameter of 1 cm.

Rapid reversed-phase high-performance liquid chromatography method for quantitation, at high pH, of the recombinant apolipoprotein A-IMilano in Escherichia coli fermentation broth

An automated reversed-phase high-performance liquid chromatography method for quantitative determination of recombinant apolipoprotein A-IMilano (r-Apo A-IM) in E. coli fermentation broth has been developed and evaluated. The use of a unique matrix (Poros IIR/H) makes it possible to achieve rapid separation and good resolution at high pH. The r-Apo A-IM-containing fraction is well separated from other proteins allowing a reliable quantification. The automation and high sample throughput of this method makes it very useful for routine determination of r-Apo A-IM in fermentation broth and in eluates from the various purfication steps. With suitable modifications and adaptions this method is likely to be useful for similar rapid analytical determination of recombinant proteins in complex solutions.