Bifunctional purine biosynthesis protein PURH is a protein that in humans is encoded by the ATIC gene. [5] [6] [7]
ATIC encodes an enzyme which generates inosine monophosphate from aminoimidazole carboxamide ribonucleotide (AICA ribonucleotide).
It has two functions:
In this step, AICA ribonucleotide is formylated, with the formyl group being transferred from the cofactor 5,10-methylenetetrahydrofolate (5,10-CH2-THF). [8]
This enzyme forms the purine ring of inosine monophosphate by dehydration and cyclisation of N-formyl AICA ribonucleotide. [9]