SAICAR => AICAR + Fumarate

Stable Identifier
Homo sapiens
5'-phosphoribosyl-5-aminoimidazole-4-N-succinocarboxamide (SAICAR) <=> 5'-phosphoribosyl-5-aminoimidazole-4-carboxamide (AICAR) + fumarate
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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
10958654 Clinical, biochemical and molecular genetic correlations in adenylosuccinate lyase deficiency

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

Hum Mol Genet 2000
8366112 Expression, purification, and kinetic characterization of recombinant human adenylosuccinate lyase

Zalkin, H, Stone, RL, Dixon, JE

J Biol Chem 1993
18388293 Reversible compartmentalization of de novo purine biosynthetic complexes in living cells

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

Science 2008
Catalyst Activity

(S)-2-(5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamido) succinate lyase (fumarate-forming) activity of ADSL tetramer [cytosol]

Orthologous Events
Cross References
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