MDA (Malondialdehyde) is a highly reactive three carbon dialdehyde produced as a byproduct of polyunsaturated fatty acid peroxidation and arachidonic acid metabolism. MDA readily combines with several functional groups on molecules including proteins, lipoproteins, and DNA.

MDA-modified proteins may show altered physico-chemical behavior and antigenicity. Antibodies to MDA will help to visualize the MDA-adducts.

Lipid peroxidation is a well-established mechanism of cellular injury in both plants and animals, and is used as an indicator of oxidative stress in cells and tissues. Lipid peroxides, derived from polyunsaturated fatty acids, are unstable and decompose to form a complex series of compounds.

These include reactive carbonyl compounds, which is the most abundant malondialdehyde (MDA). Therefore, measurement of malondialdehyde is widely used as an indicator of lipid peroxidation.

Increased levels of lipid peroxidation products have been associated with a variety of chronic diseases in both humans and model systems. MDA reacts readily with amino groups on proteins and other biomolecules to form a variety of adducts, including cross-linked products.

MDA also forms adducts with DNA bases that are mutagenic and possibly carcinogenic. DNA-protein cross-links are another result of the reaction between DNA and MDA.