Saicar
SAICAR (or (S)-2-[5-Amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamido]succinate) is a substrate for the multifunctional protein ADE2. SAICAR is an intermediate in purine metabolism. (S)-2-[5-Amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamido]succinate is converted from 5-Amino-1-(5-phospho-D-ribosyl) imidazole-4-carboxylate via phosphoribosylaminoimidazole-succinocarboxamide synthase [EC: 6.3.2.6] or SAICAR synthase. This enzyme catalyses the seventh step out of ten in the biosynthesis of purine nucleotides. The appearance of succinylaminoimidazolecarboxamide riboside (SAICAriboside) and succinyladenosine (S-Ado) in cerebrospinal fluid, urine, and to a lesser extent in plasma is characteristic of a heritable deficiency Adenylosuccinate lyase deficiency. .