Component X of mammalian pyruvate dehydrogenase complex: structural and functional relationship to the lipoate acetyltransferase (E2) component.
The lipoate acetyltransferase (E2, Mr 70,000) and protein X (Mr 51,000) subunits of the bovine pyruvate dehydrogenase multienzyme complex (PDC) core assembly are antigenically distinct polypeptides. However comparison of the N-terminal amino acid sequence of the E2 and X polypeptides reveals significant homology between the two components. Selective tryptic release of the 14C-labelled acetylated lipoyl domains of E2 and protein X from native PDC generates stable, radiolabelled 34 and 15 kDa fragments, respectively. Thus, in contrast to E2 which contains two tandemly-arranged lipoyl domains, protein X appears to contain only a single lipoyl domain located at its N-terminus.
Neagle
J
J
Department of Biochemistry, University of Glasgow, Scotland.
De Marcucci
O
O
Dunbar
B
B
Lindsay
J G
JG
D000123:Acetyltransferases / Q000032:analysis* / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D051047:Dihydrolipoyllysine-Residue Acetyltransferase; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010449:Peptide Mapping; D010455:Peptides / Q000032:analysis*; D011768:Pyruvate Dehydrogenase Complex / Q000032:analysis* / Q000276:immunology; D051381:Rats; D013552:Swine
D010455:Peptides; D011768:Pyruvate Dehydrogenase Complex; C489061:pyruvate dehydrogenase complex component X, Bos taurus; D000123:Acetyltransferases; D051047:Dihydrolipoyllysine-Residue Acetyltransferase