cDNA Cloning of the Human Peroxisomal Enoyl-CoA Hydratase: 3-Hydroxyacyl-CoA Dehydrogenase Bifunctional Enzyme and Localization to Chromosome 3q26.3-3q28: A Free Left Alu Arm Is Inserted in the 3′ Noncoding Region

Enoyl-CoA hydratase:3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme is one of the four enzymes of the peroxisomal β-oxidation pathway. Here, we report the full-length human cDNA sequence and the localization of the corresponding gene on chromosome 3q26.3-3q28. The cDNA sequence spans 3779 nucleotides with an open reading frame of 2169 nucleotides. The tripeptide SKL at the carboxy terminus, known to serve as a peroxisomal targeting signal, is present. DNA sequence comparison of the coding region showed an 80% homology between human and rat bifunctional enzyme cDNA. The 3′ noncoding sequence contains 117 nucleotides homologous to an Alu repeat. Based on sequence comparison, we propose that these nucleotides are a free left Alu arm with 86% homology to the Alu-J family. RNA analysis shows one band with highest intensity in liver and kidney. This cDNA will allow in-depth studies of molecular defects in patients with defective peroxisomal bifunctional enzyme. Moreover, it will also provide a means for studying the regulation of peroxisomal β-oxidation in humans.