The human pyruvate dehydrogenase complex: a polymorphic region of the lipoate acetyl transferase (E2) subunit gene.

A major issue in the study of the pathogenesis of primary biliary cirrhosis is whether the E2 subunit of the pyruvate dehydrogenase complex (PDH-E2), the major autoantigen in the disease, exists as a tissue-specific isoform. cDNA clones spanning a segment of the 3'-catalytic region of PDH-E2 (nt 1158-1361) have been isolated from human kidney, placenta and bile epithelium cells. Nucleotide sequence analysis of the clones showed differences consistent with the presence of normal variants of PDH-E2 in the human population. However, the existence of tissue-specific isoforms of PDH-E2 cannot yet be discounted.