AMBP Human

Alpha 1-microglobulin (A1M), a member of the lipocalin superfamily (kernal lipocalins), is a low molecular weight protein found in plasma. Distributed in plasma and extravascular compartments of all organs, A1M is present in mammals, birds, amphibians, and fish. The liver and kidney are the primary sites of A1M synthesis. Three lysyl residues, located near the opening of the lipocalin pocket, carry a yellow-brown modification resulting from the binding and degradation of heme and kynurenin (a tryptophan metabolite). A1-Microglobulin's reductase and dehydrogenase exhibit broad biological substrate specificity due to the free cysteine side-chain located in a flexible loop. Three separate carbohydrate chains glycosylate Alpha-1-microglobulin: two complex carbohydrates N-linked to asparagines at residues 17 and 96, and a simple carbohydrate O-linked to threonine at position 5. These carbohydrates constitute 22% of the protein's total molecular mass, with variations in glycosylation observed across species. A1M exists in two forms: a free form and complexed to other macromolecules. In humans, it complexes with immunoglobulin A (IgA), while in rats, it complexes with alpha-1-inhibitor-3. The free form of A1M exhibits exceptional charge heterogeneity (hence its alternate name, protein HC) and is tightly bound to a chromophore. This monomeric protein comprises 188 residues and contains three cysteines, with two (residues 75 and 173) forming a conserved intra-molecular disulphide link. The chromophoric group is covalently attached to the free cysteine at position 34. While A1M binds retinol as a major ligand, this binding is likely distinct from its covalent chromophore. Approximately half of all human plasma A1M (around 0.03mg/ml) forms a 1:1 complex with about 5% of plasma immunoglobulin A. These macromolecular complexes have a molecular weight of 200,000 and a plasma concentration of 0.3mg/ml. The complex can exhibit both antibody activity and influence many biological actions of free Alpha-1-microglobulin. Initially discovered in pathological human urine, A1M was suggested to be involved in tissue defense against reactive oxygen species and oxidation by heme and kynurenin. Evidence also points to A1M's role in regulating the immune system. A1M is involved in several functions, including: inhibition of protein antigen-induced stimulation of cultured lymphocytes; induction of lymphocyte cell division (a mitogenic effect that can be enhanced or inhibited by other plasma components); inhibition of neutrophil granulocyte migration in vitro; and inhibition of chemotaxis.

Alpha 1-microglobulin (A1M) is an immunomodulatory protein with a wide range of potential clinical uses. It shows promise as a marker for assessing tubular function.

Sterile Filtered Off-White lyophilized (freeze-dried) powder.

Lyophilized from 0.02M NH₄HCO₃. May contain traces of buffer salts.

It is recommended to use a phosphate buffer with a pH greater than 7.0 containing 0.15M NaCl.

Human A1M, while stable at room temperature for 3 weeks, should be stored between 2-8°C.

Greater than 96.0%.

The starting material has been tested and certified negative for HIV I & II antibodies, Hepatitis B surface antigen, and Hepatitis C antibodies.

Alpha-1 Microglobulin, A1M.

Purified from the urine of patients with chronic renal tubular proteinuria.