Chao_2018_Chem.Biol.Interact_291_220

Reference

Title : The inhibition, reactivation and mechanism of VX-, sarin-, fluoro-VX and fluoro-sarin surrogates following their interaction with HuAChE and HuBuChE - Chao_2018_Chem.Biol.Interact_291_220
Author(s) : Chao CK , Balasubramanian N , Gerdes JM , Thompson CM
Ref : Chemico-Biological Interactions , 291 :220 , 2018
Abstract : In this study, the mechanisms of HuAChE and HuBChE inhibition by Me-P(O) (OPNP) (OR) [PNP = p-nitrophenyl; R = CH(2)CH(3), CH(2)CH(2)F, OCH(CH(3))(2), OCH(CH(3)) (CH(2)F)] representing surrogates and fluoro-surrogates of VX and sarin were studied by in vitro kinetics and mass spectrometry. The in vitro measures showed that the VX- and fluoro-VX surrogates were relatively strong inhibitors of HuAChE and HuBChE (k(i) - 10(5)-10(6) M(-1)min(-1)) and underwent spontaneous and 2-PAM-mediated reactivation within 30 min. The sarin surrogates were weaker inhibitors of HuAChE and HuBChE (k(i) - 10(4)-10(5) M(-1)min(-1)), and in general did not undergo spontaneous reactivation, although HuAChE adducts were partially reactivatable at 18 h using 2-PAM. The mechanism of HuAChE and HuBChE inhibition by the surrogates was determined by Q-TOF and MALDI-TOF mass spectral analyses. The surrogate-adducted proteins were trypsin digested and the active site-containing peptide bearing the OP-modified serine identified by Q-TOF as triply- and quadruply-charged ions representing the respective increase in mass of the attached OP moiety. Correspondingly, monoisotopic ions of the tryptic peptides representing the mass increase of the OP-adducted peptide was identified by MALDI-TOF. The mass spectrometry analyses validated the identity of the OP moiety attached to HuAChE or HuBChE as MeP(O) (OR)-O-serine peptides (loss of the PNP leaving group) via mechanisms consistent with those found with chemical warfare agents. MALDI-TOF MS analyses of the VX-modified peptides versus time showed a steady reduction in adduct versus parent peptide (reactivation), whereas the sarin-surrogate-modified peptides remained largely intact over the course of the experiment (24 h). Overall, the presence of a fluorine atom on the surrogate modestly altered the rate constants of inhibition and reactivation, however, the mechanism of inhibition (ejection of PNP group) did not change.
ESTHER : Chao_2018_Chem.Biol.Interact_291_220
PubMedSearch : Chao_2018_Chem.Biol.Interact_291_220
PubMedID: 29920286

Related information

Inhibitor IMP-pNPIMP-pNP-FNEMP-FNEMP

Citations formats

Chao CK, Balasubramanian N, Gerdes JM, Thompson CM (2018)
The inhibition, reactivation and mechanism of VX-, sarin-, fluoro-VX and fluoro-sarin surrogates following their interaction with HuAChE and HuBuChE
Chemico-Biological Interactions 291 :220

Chao CK, Balasubramanian N, Gerdes JM, Thompson CM (2018)
Chemico-Biological Interactions 291 :220

Array
(
    [id] => 50095
    [paper] => Chao_2018_Chem.Biol.Interact_291_220
    [author] => Chao CK || Balasubramanian N || Gerdes JM || Thompson CM
    [year] => 2018
    [title] => The inhibition, reactivation and mechanism of VX-, sarin-, fluoro-VX and fluoro-sarin surrogates following their interaction with HuAChE and HuBuChE
    [journal] => Chemico-Biological Interactions
    [volume] => 291
    [page] => 220
    [medline] => 29920286
    [abstract] => Chao_2018_Chem.Biol.Interact_291_220
    [kin_reference] => 
    [mutation] => 
    [kinetic_parameter] => 
    [inhibitor] => IMP-pNP || IMP-pNP-F || NEMP-F || NEMP
    [kin_value] => 
    [substrate] => 
    [gene_locus] => Array
        (
        )

    [family] => 
    [interact_gene_locus] => 
    [xenobiotic_sensitivity] => 
    [news] => 
    [likid_reference] => 
    [lip_reference] => 
    [gene_locus_frgt] => 
    [structure] => 
    [comment] => 
    [chemical] => 
    [arpigny_jaeger] => 
    [reactivator] => 
    [disease] => 
    [enzyme] => 
    [risk_factor] => 
    [tissue] => 
    [sub_tissue] => 
    [activity] => 
    [specific_activity] => 
    [disease_by_interaction] => 
    [abstract_text] => Array
        (
            [id] => 206512
            [longtext] => Chao_2018_Chem.Biol.Interact_291_220
            [content] => In this study, the mechanisms of HuAChE and HuBChE inhibition by Me-P(O) (OPNP) (OR) [PNP = p-nitrophenyl; R = CH(2)CH(3), CH(2)CH(2)F, OCH(CH(3))(2), OCH(CH(3)) (CH(2)F)] representing surrogates and fluoro-surrogates of VX and sarin were studied by in vitro kinetics and mass spectrometry. The in vitro measures showed that the VX- and fluoro-VX surrogates were relatively strong inhibitors of HuAChE and HuBChE (k(i) - 10(5)-10(6) M(-1)min(-1)) and underwent spontaneous and 2-PAM-mediated reactivation within 30 min. The sarin surrogates were weaker inhibitors of HuAChE and HuBChE (k(i) - 10(4)-10(5) M(-1)min(-1)), and in general did not undergo spontaneous reactivation, although HuAChE adducts were partially reactivatable at 18 h using 2-PAM. The mechanism of HuAChE and HuBChE inhibition by the surrogates was determined by Q-TOF and MALDI-TOF mass spectral analyses. The surrogate-adducted proteins were trypsin digested and the active site-containing peptide bearing the OP-modified serine identified by Q-TOF as triply- and quadruply-charged ions representing the respective increase in mass of the attached OP moiety. Correspondingly, monoisotopic ions of the tryptic peptides representing the mass increase of the OP-adducted peptide was identified by MALDI-TOF. The mass spectrometry analyses validated the identity of the OP moiety attached to HuAChE or HuBChE as MeP(O) (OR)-O-serine peptides (loss of the PNP leaving group) via mechanisms consistent with those found with chemical warfare agents. MALDI-TOF MS analyses of the VX-modified peptides versus time showed a steady reduction in adduct versus parent peptide (reactivation), whereas the sarin-surrogate-modified peptides remained largely intact over the course of the experiment (24 h). Overall, the presence of a fluorine atom on the surrogate modestly altered the rate constants of inhibition and reactivation, however, the mechanism of inhibition (ejection of PNP group) did not change.
        )

)