Protein AMBP belongs to the calycin superfamily and Lipocalin family. AMBP can be cleaved into three chains: α-1-microglobulin, inter-α-trypsin inhibitor light chain and trypstatin. AMBP is expressed by the liver and secreted in plasma. α-1-microglobulin occurs in many physiological fluids including the plasma, urine, and cerebrospinal fluid. Inter-α-trypsin inhibitor is present in the plasma and urine. α-1-microglobulin occurs as a monomer and also in complexes with IgA and albumin, Inter-α-trypsin inhibitor inhibits trypsin, plasmin and lysosomal granulocytic elastase. Trypstatin act as a trypsin inhibitor, exists in a monomer forms and also occurs as a complex with tryptase in mast cells.