uracil catabolic process

Definition

Target type: biologicalprocess

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

Uracil catabolism is a crucial biological process responsible for the breakdown of uracil, a pyrimidine base found in RNA. This process occurs in all living organisms and plays a vital role in maintaining cellular homeostasis, preventing the accumulation of potentially harmful uracil, and providing precursors for other metabolic pathways.

The process typically begins with the conversion of uracil to dihydrouracil by the enzyme dihydrouracil dehydrogenase. Dihydrouracil is then further degraded to β-ureidopropionic acid by the enzyme dihydropyrimidine dehydrogenase. β-ureidopropionic acid can then undergo either of two pathways:

1. **Direct conversion to β-alanine:** This pathway involves the action of the enzyme β-ureidopropionase, which removes urea from β-ureidopropionic acid to generate β-alanine.
2. **Hydrolysis to N-carbamoyl-β-alanine:** This pathway involves the action of the enzyme β-ureidopropionase to yield N-carbamoyl-β-alanine, followed by the action of carbamoyl-β-alanine amidohydrolase to convert N-carbamoyl-β-alanine to β-alanine and carbamic acid. Carbamic acid quickly decomposes to carbon dioxide and ammonia.

β-alanine, the final product of uracil catabolism, can be further metabolized to acetyl-CoA, which serves as a crucial energy source in the cell. Alternatively, it can be incorporated into the biosynthesis of pantothenate, a precursor for coenzyme A.

The uracil catabolic process is tightly regulated to ensure that it is balanced with the synthesis of pyrimidines and the maintenance of cellular nucleotide pools. Dysregulation of this process can lead to the accumulation of uracil, which can have detrimental consequences for cellular function and potentially contribute to the development of diseases such as cancer.
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Proteins (1)

Compounds (4)