Protocol for purification of a rat blood serum protein fraction enriched in gamma-butyrobetaine esterase activity

Although described some time ago, gamma-butyrobetaine esters and related compounds have not gained much attention from researchers, and their physiological function remains obscure. Formerly we detected GBB-esterase enzymatic activity in rat blood serum. The aim of the present work was to develop a protocol that would enable purification of the protein fraction enriched in GBB esterase activity from rat blood serum. Chromatography on DEAE Sepharose at pH 4.2 enabled to purify a protein fraction enriched in enzymatic activity, but represented by numerous polypeptides. Following separation of this fraction by means of chromatography on DEAE Sepharose at pH 6.5 or heparin Sepharose chromatography at pH 7.0 did not lead to significant decrease of polypeptide number. When the above fraction was further fractionated by means of DEAE Sepharose chromatography at pH 7.4 or Bio Gel P150 chromatography the enzymatic activity was lost. Combination of DEAE Sepharose at pH 4.2 and affinity chromatography with procainamide appears to be the most suitable approach.