In the present study, the dihydrolipoamide succinyltransferase gene of the 2-oxoglutarate dehydrogenase complex was isolated from a human genomic DNA library and its entire nucleotide sequence was determined. This gene was approximately 23 kbp in size with 15 exons and 14 introns. All of the donor and acceptor splice sites of this gene conformed to the GT/AG rule. A quanine residue 43 bases upstreams of the ATG initiating translation codon was the transcription initiation site of the human dihydrolipoamide succinyltransferase mRNA. Sequence analysis of the promoterregulatory region showed the presence of a CAAT-box-like sequence but the presence of a TATAbox-like sequence was not evidenced. Also located in this region were sequences resembling glucocorticoid-responsive and CAMP-responsive elements, and an Spl binding site. No nucleotide sequence corresponding to the E3-binding and/or El-binding domain was found in any region of the gene. Therefore, the exon coding for the E3-binding and/or El-binding domain may have been lost from the gene during evolution. Moreover, a processed pseudogene of dihydrolipoamide succinyltransferase was isolated and sequenced. The nucleotide sequence of the pseudogene is 93 % similar to the sequence of the human dihydrolipoamide succinyltransferase cDNA, but the pseudogene is not functional for base changes, deletions and insertions of the pseudogene. Southern-blot analysis showed the presence of a single copy of this gene and a single copy of a pseudogene in the human genome. In addition, a possible relationship between dihydrolipoamide succinyltransferase and familial Alzheimer's disease is discussed The 2-oxoglutarate dehydrogenase complex belongs to a family of 2-oxoacid dehydrogenase complexes, which includes the pyruvate dehydrogenase complex and branchedchain 2-oxoacid dehydrogenase complex [l -61. These complexes are composed of three different enzymes, 2-oxoacid decarboxylase (El), dihydrolipoamide acyltransferase (E2) and dihydrolipoamide dehydrogenase (E3) [l -61. In mammals, the three complexes are localized in mitochondria and catalyze the oxidative decarboxylation of 2-oxoacids [l -61.Correspondence to S. Matuda, Department of Biology, Kanoya National Institute of Fitness and Sports, Kanoya, Kagoshima 891-23 JapanAbbreviations. E l , 2-oxoglutarate decarboxylase (or 2-oxoacid decarboxylase); E2, dihydrolipoamide succinyltransferase (or dihydrolipoamide acyltransferase); E3, dihydrolipoamide dehydrogenase ; E2 cDNA, human dihydrolipoamide succinyltransferase cDNA; CD4, a T cell cell-surface glycoprotein.Enzymes. 2-Oxoglutarate decarboxylase (EC 1.2.4.2) ; dihydrolipoamide succinyltransferase (EC 2.3.1.61) ; dihydrolipoamide dehydrogenase (EC 1.8.1.4).Note. The novel nucleotide sequence data published here have been submitted to the GSDB, DDBJ, EMBL and NCBl sequence data bank(s) and are available under accession number(s) D26535 and D29970.The skeletal structure of 2-oxoglutarate dehydrogenase complex is formed by the self-assembly of multiple copies of dihydrolipoamid...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.