Publications

• The pyruvate-phosphate dikinase reaction. The fate of phosphate and the equilibrium.

  Reeves R.E., Menzies R.A., Hsu D.S.

  J Biol Chem 243:5486-5491(1968) [PubMed] [EuropePMC]

• Pyruvate,phosphate dikinase from Bacteroides symbiosus.

  Reeves R.E.

  1. An improved method is given for preparation of pyruvate,phosphate dikinase from Bacteroides symbiosus. 2. The bacterial enzyme is stable, free from interfering enzyme activities, and does not require thiol compounds to maintain stability during storage or assay. 3. New direct assays of enzyme a ... >> More

  1. An improved method is given for preparation of pyruvate,phosphate dikinase from Bacteroides symbiosus. 2. The bacterial enzyme is stable, free from interfering enzyme activities, and does not require thiol compounds to maintain stability during storage or assay. 3. New direct assays of enzyme activity are based on acid evolution or consumption as measured at constant pH in a pH-stat. 4. The optimum rate of reaction in the direction of pyruvate formation occurs at about pH6.4; in the direction of phosphoenolpyruvate formation, it is at pH7.2-7.8. 5. Newly determined substrate K(m) values for the enzyme are: AMP, 3.5x10(-6)m; ATP, 1x10(-4)m; pyruvate, 8x10(-5)m; P(i), 6x10(-4)m. 6. K(+) may substitute for NH(4) (+) in activating the reaction catalysed by the B. symbiosus enzyme. 7. In the direction of pyruvate formation the bivalent metal ion requirement of the enzyme is fulfilled by salts of nickel, manganese, magnesium and cobalt. In the other direction only magnesium salts were effective. 8. The nucleotide specificity of the enzyme is strictly limited to the adenine nucleotides. CTP and ITP strongly inhibit the reaction in the direction of phosphoenolpyruvate formation. << Less

  Biochem J 125:531-539(1971) [PubMed] [EuropePMC]

• The mechanism of the phosphoenolpyruvate synthase reaction.

  Cooper R.A., Kornberg H.L.

  Biochim. Biophys. Acta 141:211-213(1967) [PubMed] [EuropePMC]

• A new enzyme with the glycolytic function of pyruvate kinase.

  Reeves R.E.

  J Biol Chem 243:3202-3204(1968) [PubMed] [EuropePMC]

• Phosphoenolpyruvate synthetase from the hyperthermophilic archaeon Pyrococcus furiosus.

  Hutchins A.M., Holden J.F., Adams M.W.W.

  Phosphoenolpyruvate synthetase (PpsA) was purified from the hyperthermophilic archaeon Pyrococcus furiosus. This enzyme catalyzes the conversion of pyruvate and ATP to phosphoenolpyruvate (PEP), AMP, and phosphate and is thought to function in gluconeogenesis. PpsA has a subunit molecular mass of ... >> More

  Phosphoenolpyruvate synthetase (PpsA) was purified from the hyperthermophilic archaeon Pyrococcus furiosus. This enzyme catalyzes the conversion of pyruvate and ATP to phosphoenolpyruvate (PEP), AMP, and phosphate and is thought to function in gluconeogenesis. PpsA has a subunit molecular mass of 92 kDa and contains one calcium and one phosphorus atom per subunit. The active form has a molecular mass of 690+/-20 kDa and is assumed to be octomeric, while approximately 30% of the protein is purified as a large ( approximately 1.6 MDa) complex that is not active. The apparent K(m) values and catalytic efficiencies for the substrates pyruvate and ATP (at 80 degrees C, pH 8.4) were 0.11 mM and 1.43 x 10(4) mM(-1). s(-1) and 0.39 mM and 3.40 x 10(3) mM(-1) x s(-1), respectively. Maximal activity was measured at pH 9.0 (at 80 degrees C) and at 90 degrees C (at pH 8.4). The enzyme also catalyzed the reverse reaction, but the catalytic efficiency with PEP was very low [k(cat)/K(m) = 32 (mM. s(-1)]. In contrast to several other nucleotide-dependent enzymes from P. furiosus, PpsA has an absolute specificity for ATP as the phosphate-donating substrate. This is the first PpsA from a nonmethanogenic archaeon to be biochemically characterized. Its kinetic properties are consistent with a role in gluconeogenesis, although its relatively high cellular concentration ( approximately 5% of the cytoplasmic protein) suggests an additional function possibly related to energy spilling. It is not known whether interconversion between the smaller, active and larger, inactive forms of the enzyme has any functional role. << Less

  J. Bacteriol. 183:709-715(2001) [PubMed] [EuropePMC]

• Phosphoenolpyruvate synthetase of Escherichia coli. Purification, some properties, and the role of divalent metal ions.

  Berman K.M., Cohn M.

  J. Biol. Chem. 245:5309-5318(1970) [PubMed] [EuropePMC]

• A new enzyme for the interconversion of pyruvate and phosphopyruvate and its role in the C4 dicarboxylic acid pathway of photosynthesis.

  Hatch M.D., Slack C.R.

  1. An enzyme was isolated from leaves of tropical grasses that catalyses the reversible conversion of pyruvate, ATP and orthophosphate into phosphopyruvate, AMP and pyrophosphate. A requirement for Mg(2+) could not be replaced by Mn(2+) or Ca(2+). 2. By replacing orthophosphate with [(32)P]orthoph ... >> More

  1. An enzyme was isolated from leaves of tropical grasses that catalyses the reversible conversion of pyruvate, ATP and orthophosphate into phosphopyruvate, AMP and pyrophosphate. A requirement for Mg(2+) could not be replaced by Mn(2+) or Ca(2+). 2. By replacing orthophosphate with [(32)P]orthophosphate or with arsenate, evidence was provided that the orthophosphate consumed appears in pyrophosphate. 3. Without Mg(2+) or 2-mercaptoethanol the enzyme was rapidly and irreversibly inactivated. EDTA only partially replaced the requirement for the thiol compound. The enzyme was considerably more unstable at 0 degrees or when frozen than at 22 degrees . Even with the best conditions devised the enzyme lost about 25% of its activity every 3hr. 4. The activities of the enzyme in leaves of the tropical grasses sugar cane (Saccharum hybrid var. Pindar), maize (Zea mays) and sorghum (Sorghum vulgare) were comparable with their maximum photosynthesis rates. The enzyme was not detectable in leaf extracts from several other plants. 5. Its role in photosynthesis is discussed. << Less

  Biochem J 106:141-146(1968) [PubMed] [EuropePMC]