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Both cyclic AMP and a specific inducer acting in concert are required for the synthesis of many inducible enzymes in E. coli.Little enzyme is made in the absence of either. In contrast to the specific inducers which stimulate the synthesis only of the proteins required for their metabolism, cyclic AMP controls the synthesis of many proteins. Glucose and certain other carbohydrates decrease the differential rate of synthesis of inducible enzymes by lowering cyclic AMP concentrations. In the lacoperon, cyclic AMP acts at the promoter site to facilitate initiation of transcription. This action requires another protein, the cyclic AMP receptor protein. The nucleotide stimulates tryptophanase synthesis at a translational level. The action of cyclic AMP in E. colimay serve as a model to understand its action on transcriptional and translational processes in eukaryotes.

Dimethyl sulfoxide inhibits horse liver alcohol dehydrogenase. In the direction of aldehyde reduction, this inhibition is competitive with aldehyde, with an inhibition constant of 5 × 10-3M. Dimethyl sulfoxide reacts with the binary complex consisting of enzyme and the reduced form of nicotinamide -adenine dinucleotide to form a highly fluorescent ternary complex, with a dissociation constant similar to the inhibition constant. The inhibition of aldehyde reduction can be interpreted as due to competition between aldehyde and dimethyl sulfoxide for the carbonyl binding site of the above-mentioned binary complex.

(1) Spirocyclohexane-1,1-indanone (VI) has been found among the oxidation products of the hydrocarbon mixture which results when 1-beta-phenylethylcyclohexanol-1 is dehydrated, or when 1-beta-phenylethylcyclohexene is cyclized by aluminum trichloride, and its constitution has been proved by synthesis.(2) Its oxime melts at 137-137.8° (corr.). The oxime of m.p. 187.5°, reported by Cook et al. therefore must be derived from some other ketone, perhaps the trans-ketoöctahydrophenanthrene, since we were unable to isolate any oxime of m.p. 177°, the figure which they reported for this compound.