uracil metabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways involving uracil, 2,4-dioxopyrimidine, one of the pyrimidine bases occurring in RNA, but not in DNA. [GOC:go_curators]

Uracil metabolism is a fundamental biological process that involves the synthesis, degradation, and salvage of uracil, a pyrimidine base that is a key component of RNA. This process is crucial for maintaining the integrity of nucleic acids, which play critical roles in cellular function and heredity.

**Uracil Synthesis:**

Uracil is synthesized de novo from aspartate and carbamoyl phosphate. This process involves a series of enzymatic reactions catalyzed by aspartate transcarbamylase, dihydroorotase, and orotate phosphoribosyltransferase. The end product of this pathway is UMP (uridine monophosphate), the precursor to all other uracil nucleotides.

**Uracil Degradation:**

Uracil is degraded via the pyrimidine catabolic pathway. This pathway begins with the conversion of uracil to dihydrouracil by dihydropyrimidine dehydrogenase (DPD). Dihydrouracil is then further degraded to β-alanine and β-aminoisobutyrate. These byproducts are subsequently metabolized to other compounds.

**Uracil Salvage:**

Salvage pathways provide an alternative route for the production of uracil nucleotides. Uracil can be directly salvaged from the environment or from the breakdown of RNA. The salvage pathway involves the conversion of uracil to UMP by uracil phosphoribosyltransferase (UPRT).

**Regulation of Uracil Metabolism:**

Uracil metabolism is tightly regulated to ensure the optimal levels of uracil nucleotides for cellular processes. Regulation occurs at multiple levels, including:

- **Enzyme activity:** The activities of key enzymes involved in uracil metabolism are subject to allosteric regulation. For example, aspartate transcarbamylase is inhibited by CTP (cytidine triphosphate) and activated by ATP (adenosine triphosphate).
- **Gene expression:** The expression of genes encoding enzymes involved in uracil metabolism is regulated by various transcription factors.
- **Nutrient availability:** The availability of nutrients, such as aspartate and carbamoyl phosphate, can affect the rate of uracil synthesis.

**Clinical Significance:**

Disruptions in uracil metabolism can lead to various diseases, including:

- **Hereditary orotic aciduria:** A rare genetic disorder caused by deficiencies in the enzymes involved in uracil biosynthesis.
- **Cancer:** Uracil metabolism plays a role in the development and progression of certain cancers.
- **Immune system disorders:** Uracil metabolism is involved in the function of the immune system.

**Conclusion:**

Uracil metabolism is a complex and essential process that plays a vital role in cellular function and homeostasis. Understanding this process is crucial for developing new therapies for diseases associated with dysregulated uracil metabolism.'
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Proteins (1)

Compounds (25)