Target type: biologicalprocess
The chemical reactions and pathways resulting in the breakdown of UMP, uridine monophosphate. [GOC:go_curators]
UMP catabolism is a metabolic pathway that breaks down uridine monophosphate (UMP), a nucleoside monophosphate, into simpler molecules. This process is crucial for the recycling of nucleotides and the maintenance of cellular energy balance. Here's a detailed description of the steps involved:
1. **Degradation to Uracil:** UMP is first converted to uridine (Urd) through the action of the enzyme nucleotidase. This reaction involves the removal of a phosphate group from the 5' position of UMP.
2. **Conversion to Dihydrouracil:** Uridine is then converted to dihydrouracil (DHU) by the enzyme dihydropyrimidine dehydrogenase (DPD). This step involves the reduction of the double bond between carbons 5 and 6 of the uracil ring.
3. **Formation of β-Alanine:** Dihydrouracil is further degraded to β-alanine and carbon dioxide (CO2) through the action of the enzyme dihydropyrimidine aminohydrolase.
4. **Fate of β-Alanine:** β-alanine can then be further metabolized. It can be used in the biosynthesis of the neurotransmitter γ-aminobutyric acid (GABA) or can be degraded via β-oxidation to acetyl-CoA, a key intermediate in cellular energy production.
5. **Regulation:** UMP catabolism is tightly regulated to maintain cellular nucleotide levels. Enzyme activities are controlled by factors such as substrate availability, product inhibition, and allosteric regulation.
6. **Clinical Significance:** Deficiencies in enzymes involved in UMP catabolism, such as DPD, can lead to severe side effects from certain anticancer drugs. This is because these drugs can be converted to cytotoxic metabolites by the same enzymes involved in UMP catabolism.
In summary, UMP catabolism is a multi-step process that degrades UMP to simpler molecules, contributing to nucleotide recycling and energy production. The regulation of this pathway is vital for maintaining cellular homeostasis and ensuring proper cellular function.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Uridine phosphorylase 1 | A uridine phosphorylase 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q16831] | Homo sapiens (human) |
| 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 |
|---|---|---|---|
| doxifluridine | doxifluridine : A pyrimidine 5'-deoxyribonucleoside that is 5-fluorouridine in which the hydroxy group at the 5' position is replaced by a hydrogen. It is an oral prodrug of the antineoplastic agent 5-fluorouracil. Designed to circumvent the rapid degradation of 5-fluorouracil by dihydropyrimidine dehydrogenase in the gut wall, it is converted into 5-fluorouracil in the presence of pyrimidine nucleoside phosphorylase. | organofluorine compound; pyrimidine 5'-deoxyribonucleoside | antimetabolite; antineoplastic agent; prodrug |
| eniluracil | eniluracil: structure in first source; inactivates dihydropyrimidine dehydrogenase | pyrimidone | |
| 5-benzylacyclouridine | 5-benzyl-1-(2-hydroxyethoxymethyl)uracil : A pyrimidone that is uracil which is substituted by a 2-hydroxyethoxymethyl group at position 1 and a benzyl group at position 5. 5-benzylacyclouridine: structure given in first source | hydroxyether; primary alcohol; 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 | |||
| 3-cyano-6-hydroxy-4-methyl-2-pyridone | 3-cyano-6-hydroxy-4-methyl-2-pyridone: structure in first source | ||
| 5-vinyluracil | 5-vinyluracil: RN given refers to unlabeled parent cpd | ||
| 2,6-dihydroxy-3-cyanopyridine | 2,6-dihydroxy-3-cyanopyridine: inhibitor of 5-fluorouracil degradation |