2.4.2.7

adenine phosphoribosyltransferase

adenine phosphoribosyl transferase

AMP formation and subsequently the formation of ADP and ATP

Human (9606)

16q24[353 ],

5-Amino-4-imidazolecarboxamide can replace adenine.

"Relative to normal brain the tumors had significantly lower ATP and GTP levels, essentially normal pool sizes of purine nucleosides and bases, unchanged activities of the salvage enzymes hypoxanthine-guanine phosphoribosyltransferase, adenine phosphoribosyltransferase, and adenosine kinase (659, 456, and 98 nmol/h/mg protein, respectively) and 4-fold higher activities of IMP dehydrogenase (11.6 nmol/h/mg protein); the latter is the rate limiting enzyme for guanylate de novo synthesis." (2154328)

"The reciprocal plots for 5-phosphoribosyl-1-pyrophosphate (PRPP) of liver and hepatoma enzymes gave apparent KmS of 2 microM for adenine phosphoribosyltransferase and 4 microM for HGPRT, showing two orders of magnitude higher affinities for PRPP than that of the rate-limiting enzyme of de novo purine synthesis, amidophosphoribosyltransferase (EC 2.4.2.14) (Km = 400 to 900 microM)." (6327016)

7428

key enzyme;

"The Lesch-Nyhan syndrome is an X-linked disorder caused by a virtually complete absence of the key enzyme of purine recycling, hypoxanthine-guanine phosphoribosyltransferase (HPRT)." (10850548)

others;

"This hysteretic characteristic of AMP pyrophosphorylase may be one of the regulatory mechanisms in purine intermediary metabolism." (1148199)

feedback;

"Studies on inhibition by the reaction product suggest that AMP is a competitive inhibitor with respect to PRPP in both enzymes, with Ki values of 150 microM in Propositus and 220 microM in controlHPRT+." (14674717)

inhibitor;

"Studies on inhibition by the reaction product suggest that AMP is a competitive inhibitor with respect to PRPP in both enzymes, with Ki values of 150 microM in Propositus and 220 microM in controlHPRT+." (14674717)

phosphorylation;

epigenetic;

"Retention of an elevated CpG dinucleotide content, despite loss of sequence homology, suggests that there may be selection for CpG dinucleotides in these regions and that their maintenance may be important for APRT gene function." (3554238)

interact with TF;VHL(7428)

"Large-scale mapping of human protein-protein interactions by mass spectrometry." (17353931)

GO:0006166 (P) purine ribonucleoside salvage [P07741 ];
GO:0003999 (F) adenine phosphoribosyltransferase activity [P07741 ];
GO:0016208 (F) AMP binding [P07741 ];
GO:0006168 (P) adenine salvage [P07741 ];
GO:0005829 (C) cytosol [P07741 ];
GO:0005515 (F) protein binding [P07741 ];

cytoplasm [P07741 ];

Defects in APRT are the cause of APRT deficiency [MIM:102600];
also known as 2, 8-dihydroxyadenine urolithiasis. It is an autosomal recessive disease characterized by renal failure. Patients have 2, 8-dihydroxyadenine (DHA) urinary stones [P07741 ];

P07741

353

00029