Phosphoribosyl pyrophosphate amidotransferase

This enzyme [EC 2.4.2.14], also known as glutamine phosphoribosyl-pyrophosphate amidotransferase, catalyzes the reaction of glutamine with S-phospho-a-D-ri-bose 1-diphosphate and water to produce 5-phospho-)3-D-ribosylamine, diphosphate (or, pyrophosphate), and glutamate. 

Synthesis of 5 phosphoribosylamine from PRPP and glutamine is catalized by glutamine phosphoribosyl pyrophosphate amidotransferase. This enzyme is inhibited by the purine 5 -nucleotides, AMP, GMP, and IMP—the end-products of the pathway. This is the committed step in purine nucleotide biosynthesis. 

Phosphoribosyl pyrophosphate amidotransferase Carbon-nitrogen Glutamine amide transfer, phosphoribosyltransferase No No... 

Ribosylamine-5-phosphate pyrophosphate phospho-ribosyltransferase (glutamate-amidating) Phosphoribosyl pyrophosphate amidotransferase... 

Caskey, C. T., D. M. Ashton, and J. B. Wyngaarden. 1964. The enzymology of feedback inhibition of glutamine phosphoribosyl-pyrophosphate amidotransferase by purine ribonucleotides. J. Biol. Chem. 239 2570. 

J. H. Kim, D. Wolle, K. Haridas, R. J. Parry, J. L. Smith, and H. Zalkin, A stable carbocyclic analog of 5-phosphoribosyl-l-pyrophosphate to probe the mechanism of catalysis and regulation of glutamine phosphoribosyl-pyrophosphate amidotransferase, J. Biol Chem. 1995, 270. 17394-17399. 

Rowe, P.B. and Wyngaarden, J.B. 1968. Glutamine phosphoribosyl-pyrophosphate amidotransferase. Purification, substructure aminoacid composition and absorption spectra. J. Biol. Chem. 245 6373-6383. 

Glutamine 5-phosphoribosyl-l-pyrophosphate amidotransferase, 38 310-311 Glutamine phosphoribosylpyrophosphate amidotransferase, ground spin state variability, 38 99-100 Glutathion... 

Fe/S clusters in regulatory enzymes have been proposed to act as sensors in such a manner that, upon detection of a measurand, the cluster disintegrates and activity stops. Putative examples are NO sensing by the [2Fe-2S] cluster in the terminal enzyme of heme synthesis, ferrochelatase [8], and 02 sensing by the [4Fe-4S] cluster in the regulatory enzyme of purine nucleotide biosynthesis, glutamine 5-phosphoribosyl-l-pyrophosphate amidotransferase [9], This is of course not a catalytic activity, since the cluster is destroyed in the action. 

Wood, A. W. and Seegmiller, J. E. 1973. Properties of 5-phosphoribosyl l pyrophosphate amidotransferase from human lymphoblasts. J. Biol. Chem. 248 138. 

Phosphoribosyl-l-pyrophosphate amidotransferase (EC 2.4.2.14), which catalyzes the committed step reaction of de novo purine synthesis [Eq. (4)], has been purified 1500-fold from soybean nodules and characterized (Reynolds et al, 1984) PRAT has not been purified from other plant sources. 

Phosphoribosyl-l-pyrophosphate amidotransferase from soybean nodules, however, was clearly located in the proplastid fraction (Boland et al, 1982). Based on the location of PRAT, Boland et al (1982) suggested that the plastid might be the site of purine biosynthesis in the nodule. Subsequently they demonstrated that a plastid fraction isolated on sucrose step gradients incorporated from [ Qglycine into purines in the presence of added PRPP, gluta-... 

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