choline dehydrogenase. Choline dehydrogenase catalyzes the conversion of exogenously supplied choline into the intermediate glycine betaine aldehyde, as part of a two-step oxidative reaction leading to the formation of osmoprotectant betaine. This enzymatic system can be found in both gram-positive and gram-negative bacteria. As in Escherichia coli , Staphylococcus xylosus , and Sinorhizobium meliloti, this enzyme is found associated in a transciptionally co-induced gene cluster with betaine aldehyde dehydrogenase, the second catalytic enzyme in this reaction. Other gram-positive organisms have been shown to employ a different enzymatic system, utlizing a soluable choline oxidase or type III alcohol dehydrogenase instead of choline dehydrogenase. This enzyme is a member of the GMC oxidoreductase family (pfam00732 and pfam05199), sharing a common evoluntionary origin and enzymatic reaction with alcohol dehydrogenase. Outgrouping from this model, Caulobacter crescentus shares sequence homology with choline dehydrogenase, yet other genes participating in this enzymatic reaction have not currently been identified [Cellular processes, Adaptations to atypical conditions].

dehydrogenase, Rv0697 family. This model describes a set of dehydrogenases belonging to the glucose-methanol-choline oxidoreductase (GMC oxidoreductase) family. Members of the present family are restricted to Actinobacterial genome contexts containing also members of families TIGR03962 and TIGR03969 (the mycofactocin system), and are proposed to be uniform in function.

GMC oxidoreductase. This domain found associated with pfam00732.

Choline dehydrogenase and related flavoproteins [Amino acid transport and metabolism]

GMC oxidoreductase. This family of proteins bind FAD as a cofactor.