InterPro domain: IPR035584

This glutaminase domain is found at the N terminus of glutamine phosphoribosylpyrophosphate (PRPP) amidotransferase (GPATase), also known as amidophosphoribosyltransferase. The glutaminase domain catalyzes amide nitrogen transfer from glutamine to the appropriate substrate. In this process, glutamine is hydrolyzed to glutamic acid and ammonia. GPATase catalyzes the first step in purine biosynthesis, an amide transfer from glutamine to PRPP, resulting in phosphoribosylamine, pyrophosphate and glutamate. GPATase crystalizes as a homotetramer, but can also exist as a homodimer [ 1 ].

1. Glutamine PRPP amidotransferase: snapshots of an enzyme in action. Curr. Opin. Struct. Biol. 8, 686-94