Adenosine 5′-tetraphosphate phosphohydrolase activity is an inherent property of soluble exopolyphosphatase from yeast Saccharomyces cerevisiae

• Published in: Biochimica et biophysica acta 1998-04, Vol.1380 (2), p.232-238
• Main Authors: Guranowski, Andrzej, Starzyńska, Elżbieta, Barnes, Larry D, Robinson, Angela K, Liu, Shengjiang
• Format: Article
• Language: English
• Subjects: Acid Anhydride Hydrolases - antagonists & inhibitors; Acid Anhydride Hydrolases - metabolism; Adenine Nucleotides - metabolism; Adenosine 5′-tetraphosphate phosphohydrolase; Adenosine tetraphosphatase; Adenosine tetraphosphate; Cobalt - pharmacology; Enzyme Activation - drug effects; Enzyme Inhibitors - pharmacology; Exopolyphosphatase; Hydrogen-Ion Concentration; Hydrolysis - drug effects; Kinetics; Magnesium - pharmacology; Manganese - pharmacology; Metals, Heavy - pharmacology; Nickel - pharmacology; Nucleoside tetraphosphatase; Nucleoside tetraphosphate; p 4A; plant biochemistry; plant physiology; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - enzymology; Solubility
• ISSN: 0304-4165; 0006-3002; 1872-8006; 1878-2434
• DOI: 10.1016/S0304-4165(97)00147-5

Homogeneous soluble exopolyphosphatase (EC 3.6.1.11) from yeast Saccharomyces cerevisiae, (scPPX1) behaves as an adenosine 5′-tetraphosphate phosphohydrolase (EC 3.6.1.14). The hydrolysis of adenosine 5′-tetraphosphate (p 4A) to ATP and orthophosphate absolutely depends on one of the following cations: Co 2+>Mn 2+>Mg 2+>Ni 2+. Optimum pH is around 4.75 and the K m for p 4A estimated at that pH in 50 mM sodium acetate and at 5 mM CoCl 2 is 80±10 μM. Adenosine 5′-pentaphosphate (p 5A) is degraded under these conditions 18-fold more slowly than p 4A. Assuming that the mass of scPPX1 is 45 kDa, the calculated k cat values for p 4A and for p 5A are 723 and 40 s −1, respectively. Two other nucleoside 5′-tetraphosphates (p 4N), guanosine tetraphosphate (p 4G) and inosine tetraphosphate (p 4I), were hydrolyzed to P i and either GTP or ITP, respectively, at the same rate as that observed for the hydrolysis of p 4A. Ammonium molybdate, sodium o-vanadate and zinc chloride inhibit the hydrolysis of p 4A ( I 50 values are 0.08, 0.3 and 0.4 mM, respectively). This newly recognized `acidic' adenosine tetraphosphatase activity from yeast is compared with two `pH 8' adenosine tetraphosphatases described earlier in rabbit and yellow lupin.