The dehydrogenases of Bacterium coli.

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Abstract
II. Reduction time of methylene blue by washed Bact. coli depends on (1) temp. lag effect, (2) presence of residual O, (3) poisoning of enzymes by methylene blue, (4) affinity of the enzymes for methylene blue, (5) presence of H donators in the bacterial suspension, and (6) products of bacterial action on the substrate, which can act as further H donators. The first 4 of these tend to increase reduction time; the last 2 to decrease it. By following the rate of reduction of the dye by formic acid, succinic acid and glucose dehydrogenases, the part played by each of these is clearly brought out. Reduction times of different quantities of methylene blue are not at all proportional to the dye conc. with the formic and glucose enzymes, and by following the rates of reduction this is shown to be due to the factors considered. Methylene white does not affect rate of reduction.[long dash]III. Evidence given suggests that the coenzyme involved in dehydrogenation of glucose by Bact. coli is identical with yeast cozymase. The coenzyme of Bact. coli can be replaced by very small amts. of cozymase, and destruction of the coenzyme activity of the bacteria involves destruction of its cozymase activity. Coenzyme of glucose dehydrogenase of liver and bacterial coenzyme are interchangeable. Also, the coenzyme of hexosemonophosphate oxidation of Warburg can replace the bacterial coenzyme. These results support the view that liver coenzyme is identical with cozymase and suggest that the Warburg coenzyme contains cozymase as one of its constituents. The co-enzyme of glucose dehydrogenase of Bact. coli is contained in 3 other bacteria[long dash]Bact. alkaligenes, Bact. dispar and Bact. lactis aerogenes[long dash]which are also shown to be active as cozymase. The latter 2 of these also need a coenzyme for glucose dehydrogenation, which is replaceable by cozymase. The coenzyme of Bact. coli is also involved in glucose oxidation by 0 and in liberation of H from glucose by the enzyme glucose hydrogenlyase of this organism.

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