A radiochemical assay method for carboxylesterase, and comparison of enzyme activity towards the substrates methyl [1-14C] butyrate and 4-nitrophenyl butyrate

Sterri, Sigrun H.; Johnsen, Bjørn A.; Fonnum, Frode

doi:10.1016/0006-2952(85)90579-9

Cited by 83 publications

(22 citation statements)

References 37 publications

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“…BW284C51 at 10 À5 M, Ethopropazine at 10 À4 M are used as specific inhibitors of AChE and BuChE activities, respectively (see references in Refs. [29,30]). The percent inhibitions of red cell AChE and plasma BuChE activities obtained in each pre-treatment group are then visually compared (no statistical analysis).…”

Section: Effect Of Pyr or Hup On Blood Ache And Buchementioning

confidence: 97%

“…Resuspended cells or plasma are diluted 1 : 10 (v/v) with saponin solution (1% in distilled water) and frozen at À 80 C until they are assayed. Samples are then diluted 1 : 20 in phosphate buffer (0.1 M pH 8) and then assayed with acetylthiocholine (1 mM, assay at 28 C) or butyrylthiocholine (1 mM, assay at 28 C) as specific substrates for determination of AChE and BuChE activities, [28,29] respectively. BW284C51 at 10 À5 M, Ethopropazine at 10 À4 M are used as specific inhibitors of AChE and BuChE activities, respectively (see references in Refs.…”

Section: Effect Of Pyr or Hup On Blood Ache And Buchementioning

confidence: 99%

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Subchronic Administration of Pyridostigmine or Huperzine to Primates: Compared Efficacy Against Soman Toxicity

Lallement¹,

Demoncheaux²,

Foquin³

et al. 2002

Drug and Chemical Toxicology

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Organophosphonate (OP) nerve agents, such as soman, are potent irreversible inhibitors of central and peripheral acetylcholinesterases (AChEs). Pre-treatment of OP poisoning relies on the subchronic administration of a reversible AChE inhibitor. In the present limited study, the protective effects against soman toxicity of such compounds, i.e., the current pre-treatment pyridostigmine and huperzine, a proposed pre-treatment, are compared in primates. This is the first time primates are used to study the potential of pre-treatment with hyperzine. Indeed, previous studies with huperzine used nonprimate models which are not the most appropriate for pre-treatment in humans. Each medication is given via a subcutaneous mini-osmotic pump for 6 days at a delivery rate providing about 20% inhibition of red cell AChE activity. In this trial with only four primates, huperzine selectively inhibits red cell AChE activity whereas pyridostigmine also inhibits plasma butyrylcholinesterase (BuChE). This latter may act as endogenous scavenger of OP compounds helping to confer additional protection against OPs. During intoxication, the cumulative dose of soman needed to produce convulsions and epileptic activity is 1.55-fold higher in the animals pre-treated with huperzine compared to those pre-treated with pyridostigmine. Thus, replacing PYR by HUP for a subchronic pre-treatment of primates gives them better tolerance to the epileptic effects of soman.

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Section: Effect Of Pyr or Hup On Blood Ache And Buchementioning

confidence: 97%

Section: Effect Of Pyr or Hup On Blood Ache And Buchementioning

confidence: 99%

Subchronic Administration of Pyridostigmine or Huperzine to Primates: Compared Efficacy Against Soman Toxicity

Lallement¹,

Demoncheaux²,

Foquin³

et al. 2002

Drug and Chemical Toxicology

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“…The cell supernatant and the culture medium were assayed for carboxylesterase activity by a modification of the method of Sterri et al (36). The assay buffer contained 1 mM p-nitrophenyl butyrate, 50 mM Hepes, pH 7.5, and 1 ml of DMSO in a total volume of 10 ml.…”

Section: Transient Expression Of Hcaementioning

confidence: 99%

“…The gels were developed at 200 V, constant voltage, for 30 min. The gels were soaked in 0.1 M sodium phosphate buffer, pH 7, for 1 h and were stained for enzyme activity as described (36). The gels were rinsed with deionized water and stained for protein with a 0.1% solution of Coomassie Blue R-250.…”

Section: Purification Protocolsmentioning

confidence: 99%

“…Once the individual clones reached confluence, they were seeded into a 35-mm dish and then into a 100-mm dish. The stable clones were collected and assayed for carboxylesterase expression as described above (36). For enzyme isolation and purification, stably transfected cells were grown in 175-cm 2 flasks containing 30 ml of culture medium.…”

Section: Stable Expression Of Hcaementioning

confidence: 99%

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Expression and Partial Purification of a Recombinant Secretory Form of Human Liver Carboxylesterase

Miller

Scott

Chacko³

et al. 1999

Protein Expression and Purification

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Sensitivity of blood-clotting factors and digestive enzymes to inhibition by organophosphorus pesticides

Quistad¹,

Casida²

2000

J. Biochem. Toxicol.

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Organophosphorus pesticide toxicology is normally evaluated in relation to inhibition of cholinesterases (acetyl and butyryl), neuropathy target esterase, and carboxylesterases, with less attention given to other physiologically important hydrolases. This study considers the relative organophosphate sensitivities of the aforementioned serine hydrolases compared with purified blood‐clotting factors (thrombin, plasmin, and kallikrein) and digestive enzymes (α‐chymotrypsin, trypsin, and elastase), assayed under similar conditions. Inhibitors that we examined are organophosphorus insecticides or their activated metabolites (paraoxon, chlorpyrifos oxon, and profenofos) and other toxicants (phenyl saligenin cyclic phosphonate and tribufos) for comparison with values that are found in the literature for the fluorophosphonates (isoflurophate and sarin). Thrombin is the most sensitive blood‐clotting factor with IC‐50 values of 19 to 160 μM for tribufos, the cyclic phosphonate, isoflurophate, and profenofos; plasmin and kallikrein are less affected (IC‐50 >100 μM). α‐Chymotrypsin, trypsin, and elastase are most sensitive to the cyclic phosphonate (IC‐50 1.3–15 μM) and less so to isoflurophate, sarin, and profenofos (IC‐50 values from 3.6 to greater than 100 μM). The cholinesterases, carboxylesterase, and neuropathy target esterase are the most sensitive to inhibition with IC‐50 values for the insecticides of less than 0.001 to 0.6, 0.002 to 0.009, and 0.15 to 100 μM, respectively. The generally low potency of these organophosphates for blood‐clotting factors and digestive enzymes suggests that associated toxic effects are unlikely at sublethal doses. © 1999 John Wiley & Sons, Inc. J Biochem Toxicol 14: 51–56, 2000

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A radiochemical assay method for carboxylesterase, and comparison of enzyme activity towards the substrates methyl [1-14C] butyrate and 4-nitrophenyl butyrate

Cited by 83 publications

References 37 publications

Subchronic Administration of Pyridostigmine or Huperzine to Primates: Compared Efficacy Against Soman Toxicity

Subchronic Administration of Pyridostigmine or Huperzine to Primates: Compared Efficacy Against Soman Toxicity

Expression and Partial Purification of a Recombinant Secretory Form of Human Liver Carboxylesterase

Sensitivity of blood-clotting factors and digestive enzymes to inhibition by organophosphorus pesticides

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