SAICAR => AICAR + Fumarate

Stable Identifier
R-HSA-73800
Type
Reaction
Species
Homo sapiens
Compartment
Synonyms
5'-phosphoribosyl-5-aminoimidazole-4-N-succinocarboxamide (SAICAR) <=> 5'-phosphoribosyl-5-aminoimidazole-4-carboxamide (AICAR) + fumarate
Locations in the PathwayBrowser
Summation

The reversible conversion of 5'-phosphoribosyl-5-aminoimidazole-4-N-succinocarboxamide (SAICAR) to 5'-phosphoribosyl-5-aminoimidazole-4-carboxamide (AICAR) and fumarate is catalyzed by adenylosuccinate lyase. The active form of this enzyme is a cytosolic tetramer (Stone et al. 1993), and fluoresence microscopy of cultured human cells suggests that it may associate with other enzymes of de novo IMP biosynthesis under some metabolic conditions (An et al. 2008). The enzyme also catalyzes the conversion of adenylosuccinate to adenosine 5'-monophosphate and fumarate. Humans lacking the enzyme accumulate dephosphorylated forms of both substrates, indicating that the enzyme mediates both reactions in vivo as well (Race et al. 2000).

Participants
Participant Of
Catalyst Activity
Catalyst Activity
Title
N6-(1,2-dicarboxyethyl)AMP AMP-lyase (fumarate-forming) activity of adenylosuccinate lyase tetramer [cytosol]
Physical Entity
Activity
Orthologous Events
Cross References
Rhea