African Journal of Biotechnology Vol. 5 (20), pp. 1902-1908, 16 October 2006   

ISSN 1684–5315 © 2006 Academic Journals        

Full Length Research Paper

Affinity purification of hen egg lysozyme using sephadex G75

Rizwana Islam^{1, 2}, Jake Kite¹, Aaron S. Baker^{1, 2}, Alejandro Ching Jr.³ and M. Rafiq Islam¹*

¹Department of Chemistry/Physics, ²Missouri Academy of Mathematics, Science and  Computing, and ³Department of Agriculture, Northwest Missouri State University, Maryville, Missouri 64468, USA.

*Corresponding author. E-mail: islamr@nwmissouri.edu.  Tel: 660-562-1210.

Abbreviations: EWL, commercially available egg white lysozyme; EWP, Egg White Prep; Buffer A, 20 mM Tris-HCl containing 25 mM NaCl, pH 8.0; SDS, sodium dodecyl sulfate; PAGE, polyacrylamide gel electrophoresis.

Accepted 25 September, 2006

We found lysozyme binds Sephadex G75, a dextran-based matrix routinely used for Gel-filtration chromatography, in a pH dependent manner. The binding is rapid and specific in a buffer containing 25 mM NaCl at pH 8.0, and requires only 0.1 ml of swollen Sephadex G75 suspension per mg of lysozyme. The bound lysozyme can be eluted with NaCl concentration over 0.15 M in the same buffer in a relatively pure form. Exploiting these binding properties with Sephadex G75, chromatographic and scaled-up methods were optimized to purify lysozyme from hen eggs with over 80% yield and over 70-fold purification. This also allows faster isolation of lysozyme compared to current methods in use.

Key words: Lysozyme purification, sephadex G-75, hen eggs.