M2 Human

The M2 autoantigen serves as a significant marker for antimitochondrial antibodies (AMA), a common serological indicator found in individuals diagnosed with primary biliary cirrhosis (PBC). PBC is a severe autoimmune liver disease characterized by damage to the intrahepatic bile ducts. Molecular analysis has revealed that the M2 antigen comprises at least three distinct target proteins. The M2 proteins are classified as E2 subunits (dihydrolipoamide transferases) of various mitochondrial dehydrogenase complexes, including the pyruvate dehydrogenase complex, the branched-chain 2-oxo-acid dehydrogenase complex, and the 2-oxoglutarate dehydrogenase complex. These complexes play a crucial role in catalyzing the oxidative decarboxylation of alpha-keto-acid substrates and interact with a prosthetic lipoamide group. Located within the mitochondrial matrix, they are associated with the inner membrane. The most prevalent reactivity observed in AMA-positive PBC sera is directed against PDC-E2. While a subset of patients exhibit AMA reactivity solely against PDC-E2 (95%), a majority also display reactivity against OGDC-E2 (39-88%) and/or BCOADC-E2 (53-55%). Notably, some patients may exhibit reactivity exclusively against OGDC-E2 and/or BCOADC-E2, without any detectable PDC-E2 autoantibodies. Consequently, assays reliant on naturally sourced M2 antigen preparations, which predominantly contain PDC-E2, may fail to identify these patients.

This recombinant antigen is designed for use in both solid-phase (ELISA) and fluid-phase diagnostic assays. It consists of a mixture of E2/dihydrolipamide acyltransferase subunits derived from three distinct mitochondrial protein complexes: pyruvate dehydrogenase complex (PDC-E2) with a molecular mass of 60,630 Daltons and an isoelectric point (pI) of 5.8; 2-oxo-glutarate dehydrogenase complex (OGDC-E2) with a molecular mass of 42,301 Daltons and a pI of 6.3; and branched-chain 2-oxo-acid dehydrogenase complex (BCOADCE2) with a molecular mass of 47,321 Daltons and a pI of 6.5. The mixture contains an equal mass of each protein component. The cDNAs encoding the mature forms of human PDC-E2, OGDC-E2, and BCOADC-E2 were individually fused to a hexa-histidine purification tag.

M2 is provided in a buffer solution containing 16mM HEPES (pH 8.0), 400mM NaCl, and 20% glycerol.

This product exhibits two primary immunological functions: (1) It binds to human auto-antibodies of the IgG type. (2) It serves as a valuable reagent in standard ELISA tests (e.g., checkerboard analysis of positive/negative sera panels) and immunodot assays with positive/negative sera panels.

This product is suitable for use in Western blot analysis with anti-M2-Antigen autoantibody-positive patient sera or monoclonal anti-hexa-His-tag antibodies.

The recommended coating concentration for this product is 0.4-0.8 µg/ml, depending on the specific type of ELISA plate and coating buffer used. It is compatible with both biotinylation and iodination procedures.

For short-term storage (2-4 weeks), the product can be stored at 4°C. For extended storage, it is recommended to store the product frozen at -20°C. To maintain product integrity, avoid repeated freeze-thaw cycles.

The purity of this product is greater than 75%, as determined by SDS-PAGE analysis.

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