MOLECULAR-CLONING AND SEQUENCE-ANALYSIS OF THE CDNA FOR HUMAN MITOCHONDRIAL SHORT-CHAIN ENOYL-COA HYDRATASE

Short chain enoyl-CoA hydratase (SCEH) catalyzes the second step of the mitochondrial fatty acid beta-oxidation spiral. We isolated cDNA clones for human SCEH to facilitate investigation of the enzyme structure of the gene and to examine the genetic background of Reye's syndrome and sudden infant death. Oligo(dT)-primed and random primed human liver cDNA libraries in lambdagt11 were screened using the entire sequence of the rat SCEH cDNA as a probe. Three positive clones covered the full-length cDNA sequence with an open reading frame encoding a precursor polypeptide of 290 amino acid residues, and deduced relative molecular mass (31,280) with a putative N-terminal presequence of 29 residues, a 5'-untranslated sequence of 21 bp and a 3'-untranslated sequence of 391 bp. Comparison with the rat SCEH cDNA showed that the deduced amino acid sequence of the human SCEH precursor is 84% identical to that of the rat enzyme precursor. Northern blot analysis gave a single mRNA species of 1.6 kb in the human liver, fibroblast and muscle.