a-1-Acid glycoprotein (A1AGP) is one if the most acidic proteins found in serum. It has a molecular weight of approximately 44 kDa with a high (~45%) content of carbohydrate. The molecular weight of the non-glycosylated polypeptide is 23.03 kDa. It is a positive acute phase reactant in most, if not all, mammals. Studies in rabbits have shown that A1AGP mRNA levels increase during the acute phase response. A1AGP is purified using a combination of acid extraction, precipitation, gel filtration and ion-exchange chromatography steps.