Amidophosphoribosyltransferase (ATase), also known as glutamine phosphoribosylpyrophosphate amidotransferase (GPAT), is an enzyme that in humans is encoded by the PPAT (phosphoribosyl pyrophosphate amidotransferase) gene.
ATase is an enzyme that converts α-phosphoribosylpyrophosphate (α-PRPP) into 5-β-phosphoribosylamine. The enzyme uses the ammonia group from the glutamine side-chain. This is the committing step in de novo purine synthesis. It is allosterically inhibited by AMP, GMP, and IMP. 6TGMP (6-thioguanine monophosphate) is a pseudo inhibitor for ATase
ATase is a member of the purine/pyrimidine phosphoribosyltransferase family. This protein is a regulatory allosteric enzyme that catalyzes the first step of de novo purine nucleotide biosynthesis.
^Brayton KA, Chen Z, Zhou G, Nagy PL, Gavalas A, Trent JM, Deaven LL, Dixon JE, Zalkin H (February 1994). "Two genes for de novo purine nucleotide synthesis on human chromosome 4 are closely linked and divergently transcribed". J. Biol. Chem.269 (7): 5313–21. PMID8106516.
Iwahana H, Oka J, Mizusawa N, et al. (1993). "Molecular cloning of human amidophosphoribosyltransferase.". Biochem. Biophys. Res. Commun.190 (1): 192–200. doi:10.1006/bbrc.1993.1030. PMID8380692.
Gassmann MG, Stanzel A, Werner S (1999). "Growth factor-regulated expression of enzymes involved in nucleotide biosynthesis: a novel mechanism of growth factor action.". Oncogene18 (48): 6667–76. doi:10.1038/sj.onc.1203120. PMID10597272.
Stanley W, Chu EH (1978). "Assignment of the gene for phosphoribosylpyrophosphate amidotransferase to the pter leads to q21 region of human chromosome 4.". Cytogenet. Cell Genet.22 (1-6): 228–31. doi:10.1159/000130943. PMID752480.
Bera AK, Chen S, Smith JL, Zalkin H (1999). "Interdomain signaling in glutamine phosphoribosylpyrophosphate amidotransferase.". J. Biol. Chem.274 (51): 36498–504. doi:10.1074/jbc.274.51.36498. PMID10593947.
Zalkin H, Dixon JE (1992). "De novo purine nucleotide biosynthesis.". Prog. Nucleic Acid Res. Mol. Biol.42: 259–87. PMID1574589.
Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K, et al. (1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library.". Gene200 (1-2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID9373149.