Enzyme, adaptation deamination

Bacterial cells that grow on pyrimidines contain adaptive enzymes that carry out the following reactions. Cytosine is deaminated to give uracil and 5-methylcytosine is similarly converted to thymine. The two dihydroxypyrimides are oxidized by an enzyme that reacts with methylene blue, but not with oxygen. The products are barbituric acid and 5-methylbarbituric acid from uracil and thymine, respectively (XII). Although intact bacteria oxidize thymine completely to CO and NH , cell-free extracts have not been found to carry the oxidation beyond 5-methylbarbituric acid. Barbituric add, on the other hand, is hydrolyzed to urea and malonic acid. The urea is further hydrolyzed and the malonic acid is oxidized as its CoA derivative to form acetyl CoA and CO. ... 

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