Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The procedure of Dietz et al. (Clin. Chem. 19: 1309-1313, 1973) for plasma cholinesterase (EC 3.1.1.7) gives a background absorbance of 1.4 A when extended to erythrocyte cholinesterase (EC 3.1.1.8) measurement, because the peak absorbance of the reaction product, 5-thionitrobenzoate, coincides with the hemoglobin Soret band at 410 nm. Consequently, the precision of erythrocyte cholinesterase measurements is poor, and the test is restricted to laboratories with a spectrophotometer having a high signal-to-noise ratio. Use of the detergent benzethonium chloride (Hyamine 1622) instead of quinidine sulfate to stop enzyme action allows readings to be made at 440 nm because the hemoglobin band is shifted to 405 nm and its peak intensity is decreased. Moreover, detergent micelle interactions shift the peak absorbance of the 5-thionitrobenzoate from 410 to 435 nm. Overall, the blank absorbance is decreased to about 0.4 A. This results in an assay that is twice as precise as the previous version and is suited for use in a routine laboratory with a moderate-quality spectrophotometer. Thus erythrocyte cholinesterase measurements can readily be made, to complement plasma cholinesterase in the investigation of exposure to organophosphates.
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PMID:Improved Ellman procedure for erythrocyte cholinesterase. 682 47

Eight widely used surfactants (cetyltrimethylammonium bromide; CTAB, benzethonium chloride; Hyamine 1622, 4-nonylphenol; NP, octylphenol ethoxylate; Triton X-100, dodecylbenzene sulfonate; LAS, lauryl sulfate; SDS, pentadecafluorooctanoic acid; PFOA, and perfluorooctane sulfonate; PFOS) were selected to examine their acute toxicities and effects on oxidative stress and cholinesterase (ChE) activities in Dugesia japonica. The differences in acute toxicity among eight surfactants to planarians were at least in the range of three orders of magnitudes. The toxicity rank of surfactants according to estimated 48-h LC(50) was SDS>NP>LAS>Hyamine 1622>CTAB>Triton X-100>PFOS>PFOA. The toxicity rank of surfactants according to 96-h LC(50) was as follows: SDS>CTAB>NP>LAS>Hyamine 1622>Triton X-100>PFOS>PFOA. There were significant increases in catalase activities in planarians exposed to LAS at nominal concentrations of 0.5 or 1 mgl(-1) and to PFOS at nominal concentrations of 5 or 10 mgl(-1) after 48-h exposure. Inhibitions of ChE activities were found in planarians exposed to Hyamine 1622 at all concentrations tested, to PFOS at nominal concentration of 10 mgl(-1), to PFOA at nominal concentrations of 50 or 100 mgl(-1) and to NP at nominal concentration of 0.5 mgl(-1). A significant increase in ChE activities was also observed in planarian exposed to Triton X-100 at nominal concentration of 5 mgl(-1). The implication of ChE inhibition by NP, PFOS and PFOA on neurological and behavioral effects in aquatic animals requires further investigation.
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PMID:Effects of nonionic and ionic surfactants on survival, oxidative stress, and cholinesterase activity of planarian. 1790 7