SAICAR => AICAR + Fumarate

Stable Identifier
Reaction [transition]
Homo sapiens
5'-phosphoribosyl-5-aminoimidazole-4-N-succinocarboxamide (SAICAR) <=> 5'-phosphoribosyl-5-aminoimidazole-4-carboxamide (AICAR) + fumarate
Locations in the PathwayBrowser
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 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).

Literature References
PubMed ID Title Journal Year
8366112 Expression, purification, and kinetic characterization of recombinant human adenylosuccinate lyase

Stone, RL, Zalkin, H, Dixon, JE

J Biol Chem 1993
10958654 Clinical, biochemical and molecular genetic correlations in adenylosuccinate lyase deficiency

Race, V, Marie, S, Vincent, MF, Van den Berghe, G

Hum Mol Genet 2000
18388293 Reversible compartmentalization of de novo purine biosynthetic complexes in living cells

An, S, Kumar, R, Sheets, ED, Benkovic, SJ

Science 2008
Participant Of
Catalyst Activity
Catalyst Activity
N6-(1,2-dicarboxyethyl)AMP AMP-lyase (fumarate-forming) activity of adenylosuccinate lyase tetramer [cytosol]
Physical Entity
Orthologous Events
Cross References
Cite Us!