pyrimidine nucleobase catabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the breakdown of pyrimidine nucleobases, 1,3-diazine, organic nitrogenous bases. [GOC:go_curators]

Pyrimidine nucleobase catabolic process is a crucial pathway involved in the breakdown of pyrimidine bases, which are essential components of DNA and RNA. This process begins with the degradation of pyrimidine nucleotides into their respective nucleobases: cytosine, uracil, and thymine.

The initial step in pyrimidine catabolism involves the conversion of cytosine to uracil via deamination by the enzyme cytosine deaminase. Uracil and thymine are then further metabolized through a series of enzymatic reactions.

Uracil is first converted to dihydrouracil by dihydropyrimidine dehydrogenase (DPD). Dihydrouracil is then further metabolized by dihydropyrimidine dehydrogenase (DPD) to β-ureidopropionate, which is subsequently broken down to β-alanine and ammonia.

Thymine catabolism follows a similar pathway. Thymine is first converted to dihydrothymine by thymine reductase. Dihydrothymine is then metabolized to β-ureidoisobutyrate by dihydropyrimidine dehydrogenase (DPD). β-ureidoisobutyrate is then converted to β-aminoisobutyrate and ammonia.

The breakdown products of pyrimidine catabolism, such as β-alanine and β-aminoisobutyrate, are excreted in urine.

Pyrimidine catabolism is tightly regulated to ensure that levels of pyrimidine bases are maintained within a healthy range. Defects in this process can lead to a variety of genetic disorders, such as orotic aciduria and pyrimidine 5'-nucleotidase deficiency.

Overall, pyrimidine nucleobase catabolic process is a complex and essential pathway that plays a critical role in the metabolism of pyrimidine bases, maintaining cellular homeostasis, and preventing the accumulation of toxic intermediates. '
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Proteins (1)

Compounds (4)