Corpus ID: 21775677

Selenophosphate synthetase. Enzyme properties and catalytic reaction.

  title={Selenophosphate synthetase. Enzyme properties and catalytic reaction.},
  author={Z. Veres and I. Kim and T. Scholz and T. Stadtman},
  journal={The Journal of biological chemistry},
  volume={269 14},
Selenophosphate synthetase, the product of the selD gene, produces the biologically active selenium donor compound, monoselenophosphate, from ATP and selenide. Isolation of the enzyme and characterization of some of its physical and catalytic properties are described. Magnesium ion and a monovalent cation, K+, NH4+, or Rb+, are required for catalytic activity. Polyphosphates and other common nucleotide triphosphates do not replace ATP as substrate. The stoichiometry of the catalytic reaction… Expand
Biosynthesis of selenophosphate
The inactive purified human enzyme together with the very low determined specific activity of the E. coli enzyme suggest an essential component for the formation of selenophosphate has not been identified. Expand
Isotope exchange studies on the Escherichia coli selenophosphate synthetase mechanism.
A slow enzyme-catalyzed exchange of ADP with ATP observed in the absence of selenide implies the existence of a phosphorylated enzyme and further supports an intermediary role ofADP in the reaction. Expand
Structural Insights into the Catalytic Mechanism of Escherichia coli Selenophosphate Synthetase
The crystal structure of the C17S mutant of SPS from E. coli (EcSPS(C17S)) in apo form (without ATP bound) is reported and a catalytic mechanism for EcSPS-mediated selenophosphate synthesis is proposed. Expand
Selenophosphate Synthetase.
This study strongly implicated selenophosphate as playing a major role in E. coli selenium metabolic pathways with in vivo and in vitro studies performed. Expand
Crystal structures of catalytic intermediates of human selenophosphate synthetase 1.
The structural and enzymatic results suggest that consuming the second high-energy phosphoester bond of ATP could protect the labile product selenophosphate during catalytic reaction. Expand
Structure of selenophosphate synthetase essential for selenium incorporation into proteins and RNAs.
The crystal structures of Aquifex aeolicus SPS and its complex with adenosine 5'-(alpha,beta-methylene) triphosphate (AMPCPP) were solved and Mutational analyses revealed that Sec/Cys13 and Lys16 are essential in SPS. Expand
Catalytic properties of selenophosphate synthetases: comparison of the selenocysteine-containing enzyme from Haemophilus influenzae with the corresponding cysteine-containing enzyme from Escherichia coli.
  • G. Lacourciere, T. Stadtman
  • Biology, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 1999
A role of selenocysteine in H. influenzae that is not catalytic is suggested, based on results that revealed the Km values for the two substrates, selenide and ATP, were similar for both enzymes, however, the selencysteine-containing enzyme did not exhibit the expected higher catalytic activity. Expand
Binding Stoichiometry of a Recombinant Selenophosphate Synthetase with One Synonymic Substitution E197D to a Fluorescent Nucleotide Analog of ATP, TNP-ATP
The SPS existence in a form of tetramer in given reaction conditions, in accordance with the concentration stoichiometry of 4 moles of TNP-ATP to 1 mole of recombinant protein, is being discussed. Expand
Binding of ATP and its derivatives to selenophosphate synthetase from Escherichia coli
It has been shown that TNP-ATP can be used as a structural probe for ATP-binding sites of SPS and that SPS238 likely has one ATP- binding site removed by truncation. Expand
Active bovine selenophosphate synthetase 2, not having selenocysteine
Results support that the product of SPS2 is selenophosphate itself, which plays a role in Sec synthesis, not the addition of this enzyme. Expand