1. Xanthines such as caffeine and theobromine are cAMP-phosphodiesterase inhibitors.2. It is caused by a deficiency of the enzyme xanthine oxidase. 3. Caffeine, like other xanthines , also acts as a phosphodiesterase inhibitor. 4. This pathway also is independent of the enzyme activity of xanthine oxidase. 5. By inhibiting xanthine oxidase, it reduces uric acid production. 6. Hypoxanthine is produced from adenine, xanthine from guanine. 7. The xanthine core of caffeine contains two fused rings, a pyrimidinedione and imidazole. 8. First, guanine gets deaminated to become xanthine . 9. Synthesis of theobromine from xanthine was first reported in 1882 by Hermann Emil Fischer. 10. In the liver, theobromine is metabolized into xanthine and subsequently into methyluric acid.
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