Chemical functionalization of silica particles for purification of proteins fused glutathione S-transferase

Background: Separation and purification of proteins is a common practice in biotechnology. Glutathione S-transferase (GST) is a protein found in eukaryotic cells. GST gene fusion protein is an efficient method for purification of inducible, high level expressed recombinant proteins (1). GST (26 KD) can be fused to the N-terminus of the target proteins which has a high affinity for binding to glutathione supports. After binding, the fusion proteins can be competitively eluted from the reduced glutathione supports. Objective: The main purpose of this study is to prepare glutathione S-transferase modified carriers for purification of proteins. Materials & Methods: In this study, the fusion protein consists of Cyan Fluorescent protein (CFP) and GST tag was cloned in pGEX plasmid and expressed in a bacterial host (2). In order to prepare glutathione supports, chemical modification of silica was performed by (3-Mercaptopropyl)trimethoxysilane followed by covalent immobilization of reduced glutathione on its surface. Finally, fusion protein was eluted and purified from glutathione support. Result: This study shows that glutathione support can be efficiently used for purification of recombinant proteins. Therefor this support can aid to purification of any protein fused to the GST tag.