Phosphoribosylaminoimidazole carboxylase
- OMIM: 172439
- UniProt: P22234
The multifunctional protein ADE2 (gene name: PAICS ) is an enzyme found in vertebrates, wherein the two different enzymatic domains are fused to a protein: the Phosphoribosylaminoimidazol carboxylase ( AIRC ) and Phosphoribosylaminoimidazolsuccinocarboxamid synthase ( SAICAR synthase). These activities are part of purine biosynthesis and come in all living things before: as an individual enzymes in prokaryotes, fungi and plants, and as bifunctional enzymes in vertebrates.
Domains of the ADE2 catalyze the steps 6 and 7 of zehnschrittigen biosynthesis of IMP. The SAICAR synthase is inhibited by IMP or maleate. The human ADE2 complexed to the octamer.
Catalyzed reactions
AIRC
CO2
5 - Aminoimidazolribonukleotid (AIR) is carboxylated to 5 - aminoimidazole -4- carboxylatribonucleotid ( CAIR ).
SAICAR synthase
ATP ADP Pi
CAIR and aspartic acid are ligated with consumption of ATP.