pyrimidine ribonucleotide biosynthetic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways resulting in the formation of a pyrimidine ribonucleotide, a compound consisting of nucleoside (a pyrimidine base linked to a ribose sugar) esterified with a phosphate group at either the 3' or 5'-hydroxyl group of the sugar. [GOC:go_curators, ISBN:0198506732]

Pyrimidine ribonucleotide biosynthesis is a fundamental metabolic process that produces the pyrimidine bases uracil and cytosine, essential building blocks of DNA and RNA. This process occurs in the cytoplasm and involves a series of enzymatic reactions that convert simple precursors into complex nucleotide molecules.

The first step involves the synthesis of carbamoyl phosphate, a key intermediate, from ammonia, carbon dioxide, and ATP. This reaction is catalyzed by carbamoyl phosphate synthetase II (CPS II).

Next, carbamoyl phosphate reacts with aspartate to form carbamoylaspartate, a crucial intermediate in the pathway. This reaction is catalyzed by aspartate transcarbamoylase (ATCase).

Carbamoylaspartate is then converted to dihydroorotate in a reaction catalyzed by dihydroorotase. Dihydroorotate undergoes a series of enzymatic steps to form orotate, a key precursor of pyrimidines.

Orotate is then converted to orotidine-5'-monophosphate (OMP) by orotate phosphoribosyltransferase (OPRT). OMP undergoes a decarboxylation reaction catalyzed by orotidine-5'-phosphate decarboxylase (ODCase) to generate uridine-5'-monophosphate (UMP).

UMP can be converted to cytidine-5'-monophosphate (CMP) through a series of reactions involving kinases and amination.

The synthesis of pyrimidine nucleotides is tightly regulated, with feedback mechanisms that control the activity of key enzymes in the pathway. This ensures a balanced supply of pyrimidine nucleotides for DNA and RNA synthesis.'
"

Proteins (2)

Compounds (150)