SAICAR

Overview of SAICAR in biochemistry

Template:Infobox biochemical compound

SAICAR (N-succinyl-5-aminoimidazole-4-carboxamide ribonucleotide) is an intermediate in the purine biosynthesis pathway. It is formed from the reaction of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) with aspartate in a reaction catalyzed by the enzyme adenylosuccinate lyase.

Biochemical Role

SAICAR plays a crucial role in the de novo synthesis of purine nucleotides, which are essential for the production of DNA and RNA. The conversion of AICAR to SAICAR is a key step in the formation of inosine monophosphate (IMP), a precursor to both adenosine monophosphate (AMP) and guanosine monophosphate (GMP).

Enzymatic Reaction

The enzyme adenylosuccinate lyase catalyzes the conversion of SAICAR to adenylosuccinate, which is then converted to adenosine monophosphate (AMP) in subsequent steps. This reaction is part of the purine metabolism pathway, which is vital for cellular energy homeostasis and nucleotide synthesis.

Clinical Significance

Deficiencies in the enzymes involved in the conversion of SAICAR can lead to metabolic disorders. For example, mutations in the adenylosuccinate lyase gene can result in adenylosuccinate lyase deficiency, a rare genetic disorder that affects the central nervous system.

See Also

• Purine metabolism
• Adenylosuccinate lyase
• Nucleotide synthesis

External Links

• [PubChem Compound Summary for SAICAR](https://pubchem.ncbi.nlm.nih.gov/compound/SAICAR)
• [KEGG Pathway Database: Purine metabolism](https://www.genome.jp/kegg/pathway/map/map00230.html)