1623-15-0Relevant articles and documents
Characterization of thermophilic archaeal isopentenyl phosphate kinases
Chen, Mo,Poulter, C. Dale
, p. 207 - 217 (2010)
Archaea synthesize isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), the essential building blocks of isoprenoid compounds, from mevalonate (MVA). However, an analysis of the genomes of several members of the Archaea failed to identify genes for the enzymes required to convert phosphomevalonate (PM) to IPP in eukaryotes. The recent discovery of an isopentenyl kinase (IPK) in Methanocaldococcus jannaschii (MJ) suggests a new variation of the MVA pathway where PM is decarboxylated to give isopentenyl phosphate (IP), which is phosphorylated to produce IPP. A blast search using the MJ protein as a probe revealed a subfamily of amino acid kinases that include the fosfomycin resistance protein fomA, which deactivates the antibiotic by phosphorylation of its phosphonate residue in a reaction similar to the conversion of IP to IPP. IPK genes were cloned from two organisms identified in the search, Methanothermobacter thermautotrophicus (MTH) and Thermoplasma acidophilum (THA), and the His-tagged recombinant proteins were purified by Ni-NTA chromatography. The enzymes catalyze the reversible phosphorylation of IP by ATP, Keq=6.3 ± 1. The catalytic efficiencies (V/K) of the proteins were ~2 × 106M-1 s-1. In the reverse direction, ADP was a substrate inhibitor for THAIPK, Ki ADP=58 ±6 μM, but not forMTHIPK. Both enzymes were active over a broad range of pH and temperature. Five compounds, dimethylallyl phosphate, isopentenyl thiolophosphate, 1-butyl phosphate, 3-buten-1-yl phosphate, and geranyl phosphate, were evaluated as alternative substrates for the MTH and THA IP kinases. All of the compounds were phosphorylated, although the catalytic efficiency was low for geranyl phosphate. 2009 American Chemical Society.
α-Radiolysis of the tributyl phosphate–hydrocarbon diluent–nitric acid system
Zilberman, B. Ya.,Chistyakov
, p. 188 - 202 (2016/06/09)
α-Radiolysis of tributyl phosphate in Sintin n-paraffin diluent in equilibrium with HNO3 solutions at single “internal” irradiation from the extracted 238Pu was studied. The radiation-chemical yields (molecules/100 eV) of butyl hydrogen phosphates (BHP), carboxylic acids, carbonyl compounds, and nitro compounds upon irradiation of 20% TBP in the treated Sintin in equilibrium with 3 M HNO3 were 0.4 (at dibutyl hydrogen phosphate to monobutyl dihydrogen phosphate ratio HDBP: H2MBP = 4.3), 1.4, 0.2–0.3, and 0.2–0.3, respectively. The degradation and oxidation processes occur more deeply than under γ-irradiation. A simple volumetric method for determining carboxylic acids in the extract was developed. In the course of irradiation, the Pu(IV) oxidation state in the extract does not change, and its retention is due to the interaction with BHP at the ratio BHP: Pu = 2 in stripping with 0.02 M HNO3 and BHP: Pu = 4 in stripping with Fe(II). The retention can be eliminated by the displacing action of Np(IV).
Determination of phosphoric acid mono- and diesters in municipal wastewater by solid-phase extraction and ion-pair liquid chromatography-tandem mass spectrometry
Quintana, Jose Benito,Rodil, Rosario,Reemtsma, Thorsten
, p. 1644 - 1650 (2008/02/05)
The first analytical method for the determination of 13 phosphoric acid mono- and diesters from aqueous samples is presented. The method consists of solid-phase extraction (SPE) and ion-pair liquid chromatographic separation with tri-n-butylamine coupled to electrospray ionization tandem mass spectrometry in the negative ion mode. Due to a lack of pure standards, only 3 of the 13 esters could be quantified. SPE recoveries ranged from 71 to 112% for di-n-butyl phosphate, diphenyl phosphate, and di-(2-ethylhexyl) phosphate (DEHP) with limits of quantification from 7 to 14 ng/L for 100-mL samples. At analyte concentrations ≥1 μg/L, aqueous samples can be analyzed by direct injection without extraction. In municipal wastewater, six diesters and one monoester were unambiguously identified by comparison with synthesized reference material. DEHP showed highest concentrations of 60 and 5 μg/L in raw and treated wastewater, respectively. The detection of monoethylhexyl phosphate was confirmed by LC-Q-TOF-MS analysis, and it was found at a concentration level comparable to DEHP. Laboratory degradation tests show that phosphoric acid diesters can be formed as intermediates in the microbial degradation of trialkyl phosphates that are being used as flame retardants and plasticizers.