APOA2 stabilizes the HDL structure by its relationship with lipids, and plays a role in the HDL metabolism. APOA2 is the 2nd most abundant protein of the high density lipoprotein particles. 25% of Apo A in HDL is Apo AII. APOA2 is localized in plasma as a monomer, homodimer, or heterodimer with apolipoprotein D. Defects in APOA2 gene might cause apolipoprotein A-II deficiency or hypercholesterolemia. Levels of Apo AII in normal plasma range from 30-50 mg per 100 ml. The physiological role of the protein is unknown. Alcohol consumption, however, increases Apo AII levels. MW: 17.4 kDa. Purity ≥ 95% by SDS - PAGE