CLONING AND SEQUENCE DETERMINATION OF THE GENE ENCODING SORBITOL DEHYDROGENASE FROM SACCHAROMYCES-CEREVISIAE

The identification of a sorbitol-induced sorbitol dehydrogenase (SDH) activity from Saccharomyces cerevisiae is described. The SDH1 structur al gene was isolated from a lambda gt11 yeast genomic library using an antibody to a 40-kDa protein induced in yeast cells growing in medium containing sorbitol. The gene encodes a 357-amino-acid (aa) protein d educed from the nucleotide sequence. Comparison of the aa sequence of the yeast SDH1 with that of sheep liver SDH reveals a 63% overall simi larity. Yeast transformants containing the cloned gene carried on a mu lticopy plasmid express high levels of SDH1 only when grown on sorbito l, suggesting that the cloned gene contains both regulatory and coding sequences.