Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Improved refolding efficacy of recombinant human interferon alpha-2b via pH modulation

Aziz Dashbolaghi¹, Shohreh Khatami², Sorush Sardari³, Reza Ahangari Cohan¹, Dariush Norouzian¹

¹Department of Pilot Biotechnology; ²Department of Biochemistry; ³Drug Design and Bioinformatics Unit, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, No. 358, 12th Farvardin Ave, Jomhhoori St, Tehran, Iran, Post Code: 1316943551.

For correspondence:- Dariush Norouzian Email: dnsa@pasteur.ac.ir Tel:+82166968856

Received: 27 September 2014 Accepted: 10 February 2015 Published: 31 March 2015

Citation: Dashbolaghi A, Khatami S, Sardari S, Cohan RA, Norouzian D. Improved refolding efficacy of recombinant human interferon alpha-2b via pH modulation. Trop J Pharm Res 2015; 14(3):385-390 doi: 10.4314/tjpr.v14i3.5

© 2015 The authors.
This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest Open Access Initiative (http://www.budapestopenaccessinitiative.org/read), which permit unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited..

Abstract

Purpose: To increase the refolding yield of Recombinant Human Interferon α-2b in order to achieve a highly potent product.

Methods: Interferon α-2b inclusion body was dissolved in tris-HCl buffer containing 6 M guanidine-HCl and CuSO₄. Different refolding buffers were employed for refolding the target protein. The refolded proteins were then purified by affinity and gel filtration chromatography. The purified proteins were subjected to circular dichroism (CD) spectropolarimetry and assayed for biological activity in vitro.

Results: Increment of pH to 8.5 improved refolding efficacies from 42.28 % to 71.22 %. However, the relative potency significantly increased up to pH 8.0 (from 19353546 to 28633902, p < 0.05) and then decreased to 21081305.00 at pH 8.5. The CD spectra demonstrated that by increasing pH to 8.5, the secondary structure of the protein was altered, probably due to increase in alpha-helix from 23.7 % at pH 7.0 to 28.1 %.

Conclusion: Employing a low-cost and simple method, such as alteration of refolding buffer pH, results in higher refolding yield in downstream processing of rhIFN α-2b.

Keywords: Recombinant human interferon alpha-2b, Refolding, Circular dichroism, Spectropolarimetry, Recombinant protein, pH effect