orotate + 5-phospho-alpha-D-ribose 1-diphosphate (PRPP) <=> orotidine 5'-monophosphate (OMP) + pyrophosphate

Stable Identifier
R-HSA-73567
Type
Reaction [transition]
Species
Homo sapiens
Compartment
Synonyms
phosphoribosylation of orotate to form oritidine 5'-phosphate (OMP)
Locations in the PathwayBrowser
General
SVG |   | PPTX  | SBGN
Click the image above or here to open this reaction in the Pathway Browser
The layout of this reaction may differ from that in the pathway view due to the constraints in pathway layout

The synthesis of orotidine 5'-monophosphate (OMP) from orotate and 5-phospho-alpha-D-ribose 1-diphosphate (PRPP) is catalyzed by the orotate phosphoribosyltransferase activity of the bifunctional "uridine monophosphate synthetase (orotate phosphoribosyl transferase and orotidine 5'-decarboxylase)" protein. The reaction itself is freely reversible, but is pulled in the forward direction in vivo by the irreversible hydrolysis of pyrophosphate. While purified human protein has not been characterized in detail, the close similarity of the human gene to that encoding the well-studied hamster protein, and the demonstration that mutations in the human gene are associated with failure to convert orotate to UMP in vivo, provide convincing evidence that the human uridine monophosphate synthetase protein indeed catalyzes these two reactions (McClard et al. 1980; Suchi et al. 1997). The active form of the human protein is a dimer (Yablonski et al. 1996; Wittmann et al. 2008).

Participants
Participant Of
Catalyst Activity
Catalyst Activity
Title
orotate phosphoribosyltransferase activity of UMPS dimer [cytosol]
Physical Entity
Activity
Orthologous Events
Cross References
Rhea
Authored
Created
Cite Us!