ATP adenylyltransferase activity

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	PMID	Title & Author	Abstract	Year
0	2556364	Isolation, characterization, and inactivation of the APA1 gene encoding yeast diadenosine 5',5'''-P1,P4-tetraphosphate phosphorylase.Plateau P, Fromant M, Schmitter JM, Buhler JM, Blanquet S	The gene encoding diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) phosphorylase from yeast was isolated from a lambda gt11 library. The DNA sequence of the coding region was determined, and more than 90% of the deduced amino acid sequence was confirmed by peptide sequencing. The Ap4A phosphorylase gene (APA1) is unique in the yeast genome. Disruption experiments with this gene, first, supported the conclusion that, in vivo, Ap4A phosphorylase catabolizes the Ap4N nucleotides (where N is A, C, G, or U) and second, revealed the occurrence of a second Ap4A phosphorylase activity in yeast cells. Finally, evidence is provided that the APA1 gene product is responsible for most of the ADP sulfurylase activity in yeast extracts.	1989.0
1	2174863	Catabolism of bis(5'-nucleosidyl) tetraphosphates in Saccharomyces cerevisiae.Plateau P, Fromant M, Schmitter JM, Blanquet S	Bis(5'-adenosyl) tetraphosphate (Ap4A) phosphorylase II (P. Plateau, M. Fromant, J. M. Schmitter, J. M. Buhler, and S. Blanquet, J. Bacteriol. 171:6437-6445, 1989) was obtained in a homogeneous form through a 40,000-fold purification, starting from a Saccharomyces cerevisiae strain devoid of Ap4A phosphorylase I activity. The former enzyme behaves as a 36.8K monomer. As with Ap4A phosphorylase I, the addition of divalent cations is required for the expression of activity. Mn2+, Mg2+, and Ca2+ sustain phosphorolysis by the two enzymes, whereas Co2+ and Cd2+ stimulate only phosphorylase II activity. All bis(5'-nucleosidyl) tetraphosphates assayed (Ap4A, Ap4C, Ap4G, Ap4U, Gp4G, and Gp4U) are substrates of the two enzymes. However, Ap4A phosphorylase II shows a marked preference for A-containing substrates. The two enzymes catalyze adenosine 5'-phosphosulfate phosphorolysis or an exchange reaction between Pi and the beta-phosphate of any nucleoside diphosphate. They can also produce Ap4A at the expense of ATP and ADP. The gene (APA2) encoding Ap4A phosphorylase II was isolated and sequenced. The deduced amino acid sequence shares 60% identity with that of Ap4A phosphorylase I. Disruption of APA2 and/or APA1 shows that none of these genes is essential for the viability of Saccharomyces cerevisiae. The concentrations of all bis(5'-nucleosidyl) tetraphosphates are increased in an apa1 apa2 double mutant, as compared with the parental wild-type strain. The factor of increase is 5 to 50 times, depending on the nucleotide. This observation supports the conclusion that, in vivo, Ap4A phosphorylase II, like Ap4A phosphorylase I, participates in the catabolism rather than the synthesis of the bis(5'-nucleosidyl) tetraphosphates.	1990.0
2	2982863	Phosphorolytic cleavage of diadenosine 5',5'''-P1,P4-tetraphosphate. Properties of homogeneous diadenosine 5',5'''-P1,P4-tetraphosphate alpha, beta-phosphorylase from Saccharomyces cerevisiae.A Guranowski	Novel enzymatic activity which splits diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) phosphorolytically has been found in extracts from Saccharomyces cerevisiae. One of the two alpha,beta-anhydride bonds between Ap4A phosphate residues undergoes phosphorolysis, and ATP (pppA) plus ADP (ppA) are the products of the reaction according to the equation: AppppA + P*i----pppA + p*pA The reaction is dependent on the presence of divalent metal ions; Mn2+ or Mg2+ sustain the greatest rates of reaction. Among analogues of the Ap4A substrate, Ap5A and Gp4G, but not p4A and Ap3A, are substrates, and corresponding products are p4A plus ADP, and GTP plus GDP, the phosphate being incorporated into the nucleoside 5'-diphosphates. In the reactions, phosphate can be substituted with arsenate. Arsenolysis of Ap4A, Ap5A, or Gp4G leads to ATP plus AMP, p4A plus AMP, and GTP plus GMP, respectively. The name diadenosine tetraphosphate alpha,beta-phosphorylase (ADP-forming) is proposed for the new enzyme. The phosphorylase has been purified to apparent homogeneity and behaves as a single polypeptide chain of Mr = 40,000. Optimum activity of the enzyme is at pH 8.0 and the sulfhydryl groups are essential for catalysis. At saturating Ap4A, the rate constant for the reaction is 36 s-1 and the Km value for Ap4A is 60 microM (37 degrees C, 50 mM Hepes/KOH (pH 8.2), 500 microM MnCl2, 10 mM K2HPO4, 1 mM 2-mercaptoethanol, and 2% glycerol). The Km values for phosphate and arsenate are 1 and 3 mM, respectively.

Plateau P , Fromant M , Schmitter J M , et al. Catabolism of bis(5'-nucleosidyl) tetraphosphates in Saccharomyces cerevisiae.[J]. Journal of Bacteriology, 1990, 172(12):6892-6899.