Characterization of alkylation products of diethyl phosphorothioate

Shafik, M. T.; Bradway, Diane E.; Biros, Francis J.; Enos, Henry F.

doi:10.1021/jf60172a023

Cited by 26 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Chromatograms representing standard mixtures of trialkyl phosphates were previously presented (Shafik and Enos, 1969;Shafik et al, 1970). It has been established that quantitation should be based on ethylated DMP and DMTP and methylated DEP, DMDTP, and DEDTP; quantitation of DETP should be based on the methylated thiolate isomer.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Cleanup procedure for the determination of low levels of alkyl phosphates, thiophosphates, and dithiophosphates in rat and human urine

Shafik¹,

Bradway²,

Enos³

1971

J. Agric. Food Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

“…The preparation of standard curves, extraction of urine, and gas chromatographic determination of the methylated and ethylated alkyl phosphates have been described in a previous publication (Shafik and Enos, 1969). 0,0-Diethyl phosphorothionate is quantitated after methylation as 0,0diethyl S-methylphosphorothiolate (Shafik et al, 1970).…”

mentioning

confidence: 99%

Cleanup procedure for the determination of low levels of alkyl phosphates, thiophosphates, and dithiophosphates in rat and human urine

Shafik¹,

Bradway²,

Enos³

1971

J. Agric. Food Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…In principle, phosphorothioates can be alkylated on either sulfur or oxygen atoms. Careful studies have shown, however, that alkylation of phosphorothioate diesters preferentially produces S -alkylated rather than O -alkylated products, in agreement with a greater charge on the sulfur and the generally greater nucleophilicity of sulfur. In agreement with this result, the fitted metal positions observed in the present work were closer to the thioate than to the nonbridging oxygen atoms.…”

Section: Discussionmentioning

confidence: 99%

“…In principle, phosphorothioates can be alkylated either on sulfur or oxygen atoms. Careful studies have shown, however, that alkylation of phosphorothioate diesters preferentially produces S-alkylated rather than O-alkylated products, 31 in agreement with a greater charge on the sulfur 16 In conclusion, alkylation of a phosphorothioate group with a lanthanide tag provides a viable and generally applicable route to generate PCSs in DNA, even though the phosphodiester backbone of DNA is more solvent exposed than the sulfur atom of a cysteine residue in a typical a-helix of a protein. We anticipate that this approach will be useful for studies of protein-DNA interactions as well as for studies of RNA structure, following incorporation of deoxyribophosphorothioate linkages into the RNA to avoid phosphodiester bond cleavage.…”

Section: Introductionmentioning

confidence: 86%

New Lanthanide Tag for the Generation of Pseudocontact Shifts in DNA by Site-Specific Ligation to a Phosphorothioate Group

Lee

Carruthers

et al. 2017

Bioconjugate Chem.

View full text Add to dashboard Cite

Pseudocontact shifts (PCS) generated by paramagnetic lanthanides provide a rich source of long-range structural restraints that can readily be measured by nuclear magnetic resonance (NMR) spectroscopy. Many different lanthanide-binding tags have been designed for site-specific tagging of proteins, but established routes for tagging DNA with a single metal ion rely on difficult chemical synthesis. Here we present a simple and practical strategy for site-specific tagging of inexpensive phosphorothioate (PT) oligonucleotides. Commercially available PT oligonucleotides are diastereomers with S and R stereoconfiguration at the backbone PT site. The respective S and R diastereomers can readily be separated by HPLC. A new alkylating lanthanide-binding tag, C10, was synthesized that delivered quantitative tagging yields with both diastereomers. PCSs were observed following ligation with the complementary DNA strand to form double-stranded DNA duplexes. The PCSs were larger for the S than the R oligonucleotide and good correlation between back-calculated and experimental PCSs was observed. The C10 tag can also be attached to cysteine residues in proteins, where it generates a stable thioether bond. Ligated to the A28C mutant of ubiquitin, the tag produced excellent fits of magnetic susceptibility anisotropy (Δχ) tensors, with larger tensors than for the tagged PT oligonucleotides, indicating that the tag is not completely immobilized after ligation with a PT group.

show abstract

“…The Shafik procedure (solvent extraction, diazoalkane derivatization, flame photometric detector GC determination), for example, gives variable recoveries and is subject to interference by endogenous inorganic phosphate 14. The thiono‐thiolo rearrangement (interconversion of thiolate and thionate esters) is catalyzed by diazoalkanes 16. PFBB derivatization requires heat and causes the decomposition of some thio compounds 6, 17.…”

mentioning

confidence: 99%

Direct determination of dialkyl phosphates by strong anion‐exchange liquid chromatography/atmospheric pressure chemical ionization mass spectrometry using a quadrupole ion trap instrument

Draper

Behniwal

Wijekoon

2008

Rapid Comm Mass Spectrometry

View full text Add to dashboard Cite

The direct determination of dialkyl phosphates (DAPs) in water by strong anion-exchange (SAX) liquid chromatography/atmospheric pressure chemical ionization (APCI) mass spectrometry was investigated. The SAX high-performance liquid chromatography (HPLC) column was eluted with methanol/water gradients containing ammonium formate (AF) separating the DAPs which included six dimethyl- and diethyl-substituted phosphates, thiophosphates, and dithiophosphates. The high buffer concentrations required for separation were compatible with -ve APCI, but in +ve APCI the DAPs were unstable giving anomalous ions such as [M+15]+ and [M+29]+. These ions are believed to result from ion molecule reactions with CH3OH2+ in the plasma. DAPs are very stable in -ve APCI being detected as abundant [M-H](-) ions, even with 200 mM AF. At higher AF concentration formate clusters ([M+45](-) and [M+91](-)) were seen. Fragmentation by collision-activated dissociation (CAD) was more efficient for deprotonated ethyl-substituted DAPs which lost ethylene followed by ethanol. APCI instrument detection limits were in the low ng/mL range and the response was highly linear. Isotope dilution quantitation using d10-diethyl dithiophosphate (DEDTP) as an internal standard produced an instrument detection limit of 2 ng DEDTP/mL and method detection limit (MDL) of 9.3 ng/mL with accuracy of 99% (spike concentration, 25 ng/mL). DAP mixtures required storage in cold, dry conditions and alcohol solvents should be avoided because of solvolysis reactions.

show abstract

Characterization of alkylation products of diethyl phosphorothioate

Cited by 26 publications

References 0 publications

Cleanup procedure for the determination of low levels of alkyl phosphates, thiophosphates, and dithiophosphates in rat and human urine

Cleanup procedure for the determination of low levels of alkyl phosphates, thiophosphates, and dithiophosphates in rat and human urine

New Lanthanide Tag for the Generation of Pseudocontact Shifts in DNA by Site-Specific Ligation to a Phosphorothioate Group

Direct determination of dialkyl phosphates by strong anion‐exchange liquid chromatography/atmospheric pressure chemical ionization mass spectrometry using a quadrupole ion trap instrument

Contact Info

Product

Resources

About