Molecular cloning of human class IV alcohol dehydrogenase cDNA

A cDNA encoding a new type of alcohol dehydrogenase was cloned from a human stomach cDNA library. PCR amplification of 5’-stretch human stomach λgt11 library, using degenerate inosine-containing oligonucleotide probes compatible with peptide sequences of human σ-ADH, resulted in a single product. Subsequently, internal non-degenerate primers were constructed according to the sequences occurring in the product. By PCR with combinations its 5' and 3' ends were amplified. The full length cDNA sequence has 1125 nucleotides with a 72% similarity to those of human class I ADH. The polypeptide sequence, predicted from the cDNA, corresponds to 373 amino acids with a high degree of similarity (96%) to fragments of σ-ADH previously reported. Northern hybridization analysis with the specific probe for the mRNA of this protein showed that it is expressed in the human stomach but not in the liver. These data indicate that the cDNA we cloned is that of human class IV ADH.