Anti-E3 antibodies enable researchers to detect and measure the E3 antigen in biological samples. This target is a reported synonym of the DLD gene, which encodes dihydrolipoamide dehydrogenase. This protein is known to function in proteolysis, among other biological roles. The human version of E3 has a canonical amino acid length of 509 residues and a protein mass of 54.2 kilodaltons, although 3 isoforms have been identified. It is reported to be localized in the nucleus, mitochondria, and cytoplasmic vesicles of cells and widely expressed in many tissue types. E3 is a member of the Class-I pyridine nucleotide-disulfide oxidoreductase protein family.