A NOVEL ANCESTRAL PROTEIN OF DROSOPHILA ALCOHOL-DEHYDROGENASE IN STREPTOMYCES

Polyclonal antibodies raised against purified Drosophila alcohol dehyd rogenase (ADH) were used in Western blot analyses to search for struct urally and/or immunologically related proteins in prokaryotes and euka ryotes. No immunological-reactive was detected in a flesh fly, a locus t, and butterflies. Immunological similarity with the 50-kDa PQQ-gluco se dehydrogenase (GluDH)-B enzyme of Acinetobacter calcoaceticus was f ound, but the cross-reactivity apparently is dependent on the high hyd rophilic character of this protein. Antibodies against PQQ-GluDH did n ot recognize Drosophila ADH. In five of seven species of the gram-posi tive soil bacteria actinomycetes tested, a protein approximately 28-30 kDa in subunit size was strongly recognized by alpha-DADH. It is prob ably not one of the two proteins with known homology to Drosophila ADH , viz., the actIII gene product and 20 beta-hydroxysteroid dehydrogena se. The protein is present in both the soluble and the pellet-membrane fraction of the cells. The protein has a late temporal expression in surface-grown cultures and, therefore, might be involved in secondary metabolism.