Apoa1 also known as Apolipoprotein A-I, is the major protein component of high density lipoprotein (HDL) in plasma. This protein promotes cholesterol efflux from tissues to the liver for excretion. And it is a cofactor for lecithin cholesterolacyltransferase (LCAT) which is responsible for the formation of most plasma cholesteryl esters. Defects in the Apoa1 are associated with HDL deficiency including Tangier disease. Recombinant mouse Apoa1, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques