Enzyme Systems in Tetrahymena Geleii S* I. Anaerobic Dehydrogenases Concerned with Carbohydrate Oxidation By

In view of the present increased interest in the metabolism of the ciliate, Tetrahymena gdeii, an investigation of the relative activity of the anaerobic dehydrogenases which have a direct role in carbohydrate oxidation was undertaken as the first phase of a general survey of enzymatic activity in this organism. The presence in the ciliate of the dehydrogenases active in the tricarboxylic acid cycle was inferred from the results obtained in previous investigations. Chaix, Chauvet, and Fromageot (2) obtained slight increases in oxygen uptake if Tetrahymena was incubated with succinate and with citrate. A more conclusive demonstration of succinate oxidation by the organism was obtained by Seaman (3) and by Seaman and Houlihan (4); added citrate, however, was without effect. In these previous investigations no attempts were made to assay for maximal activity of the systems,