Abstract: Lysozyme was purified by two\|step ammonium sulfates precipitation and anion\|exchange chromatography to study the separation processing of lysozyme from egg white. The purity of lysozyme was assayed by sodium dodecyl sulfate\|polyacrylamide gel electrophoresis （SDS\|PAGE）. Egg white was diluted with five times volume of Tris\|HCl buffer and kept at 4℃ for 6 h. The supernatant was collected from precipitation with 50% saturation ammonium sulfate and subjected to precipitation with 80% saturation ammonium sulfate. The precipitant was dissolved into pH 90 Tris\|HCl and applied onto Q\|Sepharose FF anion\|exchange chromatography. High purity lysozyme was directly obtained from permeate. The specific activity of lysozyme was increased nearly 15 folds from 14413 U·mg-1 to 2 235 U·mg-1 with recovery ratio of 1576%. Not only lysozyme can be easily purified by two\|step ammonium sulfates precipitation and Q\|sepharose FF anion\|exchange chromatography but also other proteins such as acidic proteins can be easily purified with the same procedure. This procedure can simplify the separation process and reduce the cost in lysozyme separation.

Key words: egg white, lysozyme, anion\|exchange chromatography, separation