Target type: biologicalprocess
The chemical reactions and pathways resulting in the breakdown of purine nucleobases, one of the two classes of nitrogen-containing ring compounds found in DNA and RNA, which include adenine and guanine. [GOC:go_curators]
Purine nucleobase catabolic process is a fundamental metabolic pathway that breaks down purine bases, adenine and guanine, into simpler molecules. It plays a crucial role in maintaining cellular homeostasis by regulating the levels of purine nucleotides, which are essential for DNA and RNA synthesis, energy production, and signaling.
The catabolic process begins with the conversion of adenine to hypoxanthine and guanine to xanthine. Both of these molecules are then further metabolized by xanthine oxidase to uric acid. The following is a detailed breakdown of the process:
1. **Adenine Catabolism:** Adenine is first deaminated by adenine deaminase, forming hypoxanthine. Hypoxanthine is then oxidized by xanthine oxidase to xanthine, which is finally oxidized to uric acid.
2. **Guanine Catabolism:** Guanine is converted to xanthine through a two-step process. First, guanine is deaminated by guanine deaminase, forming xanthine. Xanthine is then further oxidized by xanthine oxidase to uric acid.
3. **Uric Acid Formation:** Xanthine oxidase, a key enzyme in purine catabolism, catalyzes the oxidation of hypoxanthine and xanthine to uric acid. Uric acid is the end product of purine metabolism in humans and most primates.
4. **Uric Acid Excretion:** Uric acid is primarily excreted in urine, and its concentration in the blood is tightly regulated.
Purine nucleobase catabolic process is a complex and essential pathway that is tightly regulated by various factors, including diet, genetic factors, and hormonal signals. Dysregulation of this pathway can lead to various diseases, including gout, Lesch-Nyhan syndrome, and kidney stones. The proper functioning of this pathway is critical for maintaining cellular health and overall well-being.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Dihydropyrimidine dehydrogenase [NADP(+)] | A dihydropyrimidine dehydrogenase [NADP(+)] that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q12882] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| eniluracil | eniluracil: structure in first source; inactivates dihydropyrimidine dehydrogenase | pyrimidone | |
| 5-iodouracil | 5-iodouracil : An organoiodine compound consisting of uracil having an iodo substituent at the 5-position. 5-iodouracil: RN given refers to parent cpd | organoiodine compound | antimetabolite |
| 5-cyanouracil | |||
| 5-vinyluracil | 5-vinyluracil: RN given refers to unlabeled parent cpd |