Beschreibung:
<jats:p>The recently determined primary structure of glucose dehydrogenase from <jats:italic>Bacillus megaterium</jats:italic> was scanned by computerized comparisons for similarities with known polyol and alcohol dehydrogenases. The results revealed a highly significant similarity between this glucose dehydrogenase and ribitol dehydrogenase from <jats:italic>Klebsiella aerogenes</jats:italic>. Sixty‐one positions of the 262 in glucose dehydrogenase are identical between these two proteins (23% identity), fitting into a homology alignment for the complete polypeptide chains. The extent of similarity is equivalent to that between other highly divergent but clearly related dehydrogenases (two zinc‐containing alcohol dehydrogenases, 25% sorbitol and zinc‐containing alcohol dehydrogenases, 25%; ribitol and non‐zinc‐containing alcohol dehydrogenases, 20%), and suggests an ancestral relationship between glucose and ribitol dehydrogenases from different bactera. The similarities fit into a previously suggested evolutionary scheme comprising short and long alcohol and polyol dehydrogenases, and greatly extend the former group to one composed of non‐zinc‐containing alcohol‐polyol‐glucose dehydrogenases.</jats:p>