Bifunctional purine biosynthesis protein PURH is a protein that in humans is encoded by the ATIC gene. ATIC encodes an enzyme which generates inosine monophosphate from aminoimidazole carboxamide ribonucleotide (AICA ribonucleotide). It has two functions:
EC 2.1.2.3 - 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase In this step, AICA ribonucleotide is formylated, with the formyl group being transferred from the cofactor 5,10-methylenetetrahydrofolate (5,10-CH2-THF).
EC 3.5.4.10 - IMP cyclohydrolase This enzyme forms the purine ring of inosine monophosphate by dehydration and cyclisation of N-formyl AICA ribonucleotide.
References
Further reading
External links Inosine+monophosphate+synthase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Overview of all the structural information available in the PDB for UniProt: P31939 (Human Bifunctional purine biosynthesis protein PURH (Inosine monophosphate synthase)) at the PDBe-KB.