The induction and repression of xanthine dehydrogenase (XDH) in the strain of Pseudomonas synxantha A3 were studied in the presence and absence of various carbon and nitrogen sources. Adenine and various purine compounds such as adenosine, inosine, hy...
The induction and repression of xanthine dehydrogenase (XDH) in the strain of Pseudomonas synxantha A3 were studied in the presence and absence of various carbon and nitrogen sources. Adenine and various purine compounds such as adenosine, inosine, hypoxanthine, and guanine were inducers of this enzyme. The induction of XDH in the presence of adenine was also stimulated by glucose, glycerol, and sorbitol. In contrast, the enzyme formation was inhibited by glyoxylate and ammonia, which were end-products of the degradation of adenine in this strain. The enzyme formation in the presence of adenine, even in the presence of glucose was also stimulated by some amino acids, such as glutamate and aspartate. Alanine and phenylalaine, however, inhibited the enzyme formation in the presence of glucose. In contrast to xanthine dehydrogenase, adenine deaminase in the strain A3 was suggested to be constitutively produced. Therefore, adenine degradation in the strain A3 seems to be controlled by the level of xanthine dehydrogenase involved in degradation of hypoxanthine.