An assay method for disulfide groups by fluorescence quenching

Karush, Fred; Klinman, Norman R.; Marks, Robert

doi:10.1016/0003-2697(64)90088-0

Cited by 128 publications

(39 citation statements)

References 9 publications

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“…CH3SH is known to collect efficiently on Ag-impregnated filters 20 and the bisulfide group is apparently responsible for the fluorimetric quenching interaction with FMA. Nevertheless, the method's discrimination toward CH3SH agrees with previous results showing that n-butyl mercaptan 8 and S-carboxymethyl-L-cysteine 4 do not quench the 520 nm fluorescence of FMA. …”

Section: Interferencessupporting

confidence: 80%

“…However, our results for standards prepared from Na2S are more in agreement with Axelrod et al 6 who stated a decay rate of 3 percent in 6 hours for diluted working Na2S standards. As noted by Karush et al, 4 extremely clean glassware is necessary for optimum performance of the method. Random error due to this glassware effect can be minimized by analyzing the standards immediately after their preparation.…”

Section: Stability Of Reagentsmentioning

confidence: 99%

“…Quantification is achieved by the selective quenching effects of sulfide [S"~2] (or more correctly bisulfide [HS~] since pK2 = 19 ± 2 for H2S( aq ) 3 ) on the fluorescence of fluorescein mercuric acetate (FMA). This fluorimetric procedure was initially described by Karush et al, 4 Grunert et al, 5 and Axelrod et al 6 The work described in this paper was performed as a portion of a more comprehensive evaluation of potential analytical techniques to measure natural emissions of volatile sulfur compounds. 7 The major objectives for the specific evaluation of the AgNCVfilter/FMA fluorimetric method were to: a) compare the responses of liquid sodium sulfide standards, which are normally used to calibrate the method, with gaseous H2S standards, which better simulate actual analyte and sample matrix components; b) clarify previous conflicting reports 1 ' 2 ' 8 concerning potential positive interferences from CH3SCH3 and CH3SH; c) assess the sources and magnitudes for both indeterminate and systematic errors in the sampling and fluorimetric procedures; and d) suggest modifications to the basic method and/or operational procedures that improve both analytical ruggedness and data quality.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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Performance Characterization and Optimization of the AgNO₃-Filter/FMA Fluorimetric Method for Atmospheric H₂S Measurements

Farwell¹,

Chatham²,

Barinaga³

1987

JAPCA

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This sensitive, albeit precarious, method for measuring ppb-ppt (V/V) concentrations of H 2 S was examined for various sources of potential error within the procedure. Filter preparation, filter storage, filter extraction, fluorimetric reagent stabilities, matrix differences between standards and samples, and possible interferences from other sulfur-containing compounds were separately studied for their effects on the analytical performance of the method. The overall method showed no Interference from SO 2 , CS 2 , COS, CH 3 SH, CH3SCH3, and SO 4~2 . To minimize bias and obtain a reliable estimate of precision, the method should be calibrated with H 2 S standards rather than liquid bisulfide standards. The measurement precision is a function of the quantity of H 2 S collected as Ag 2 S and/or AgSH on the impregnated filters. Because of the method's linear dynamic range, sufficient air should be sampled to achieve filter loadings of 15 to 35 ng S/filter. A quality control method based on fluoresceln mercuric acetate (FMA) is presented that ensures data quality while reducing the otherwise frequent need for fluorimetric calibration.A sensitive method for measuring low and sub-parts-perbillion (ppb V/V) concentrations of atmospheric hydrogen sulfide has been described by Natusch et al. 1 and modified by Jaeschke et al. 2 for automated field sampling. The method employs the collection of H2S on a AgNCVimpregnated filter. The filter is then leached with a basic cyanide solution to liberate the sulfide collected as Ag2S and/or AgSH on the filter. Quantification is achieved by the selective quenching effects of sulfide [S"~2] (or more correctly bisulfide [HS~] since pK2 = 19 ± 2 for H2S( aq ) 3 ) on the fluorescence of fluorescein mercuric acetate (FMA). This fluorimetric procedure was initially described by Karush et al.,4 Grunert et al., 5 and Axelrod et al. 6The work described in this paper was performed as a portion of a more comprehensive evaluation of potential analytical techniques to measure natural emissions of volatile sulfur compounds. 7 The major objectives for the specific evaluation of the AgNCVfilter/FMA fluorimetric method were to: a) compare the responses of liquid sodium sulfide standards, which are normally used to calibrate the method, with gaseous H2S standards, which better simulate actual analyte and sample matrix components; b) clarify previous conflicting reports 1 ' 2 ' 8 concerning potential positive interferences from CH3SCH3 and CH3SH; c) assess the sources and magnitudes for both indeterminate and systematic errors in the sampling and fluorimetric procedures; and d) suggest modifications to the basic method and/or operational procedures that improve both analytical ruggedness and data quality. Experimental Methods ApparatusAn Aminco-Bowman spectrophotofluorometer with an analog readout was used for the fluorimetric determinations. The excitation and emission wavelengths were 499 nm and 520 nm, respectively. Conventional fused silica cuvettes were used for the fluorimetric measurements. A...

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Section: Interferencessupporting

confidence: 80%

Section: Stability Of Reagentsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Performance Characterization and Optimization of the AgNO₃-Filter/FMA Fluorimetric Method for Atmospheric H₂S Measurements

Farwell¹,

Chatham²,

Barinaga³

1987

JAPCA

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“…FMA was purified from the mono mercuric derivatives on G50 Sephadex (1.5 × 32 cm) column in solution of 10 mM [10]. Stock solution of FMA with concentration 5 × 10 −4 M was stored in 10 mM NaOH at room temperature and can be used in experiments without additional purification over two weeks.…”

Section: Determination Of Sulfhydryl Groupsmentioning

confidence: 99%

Changes in Human Hair Induced by UV- and Gamma Irradiation

Palma¹,

González‐Gómez²,

Galicia³

et al. 2016

ABB

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The effect of UV-and 137 Cs gamma radiation on the structural and chemical integrity of human hair was studied to determine the feasibility of using human hair as a non-invasive biomarker of radiation exposure to ionized gamma-and non-ionized UV-radiation. Steady state tryptophan (Trp) fluorescence and chemical analytical methods were used to evaluate the molecular integrity of Trp fluorophores and SH-groups in hair proteins and to assess the radiation induced damage quantitatively. It was found that human hair fibers were progressively damaged by exposure to both UV-and ionized gamma radiation. Damage to the hair was evidenced by a decrease in the fluorescence intensity as a result of observed depletion of the amino acid tryptophan as well as significant reduction in a number of free SH-groups in hair proteins. Hair damage was dose-dependent for exposures between 0 and 10.0 Gy and 0 -20 J/cm 2 of UV-radiation. Additional results demonstrate that hair-fibers exposed to gamma rays, with much higher quantum energy than UV, undergo a smaller extent of changes in Trp fluorescence than when exposed to lower or equal energy of UV-irradiation. The stable Trp fluorophore appears to be extremely sensitive to UVradiation in contrast to the ionized gamma radiation whose damage is originated from the reaction of free radicals and direct deposition of energy. We conclude that fluorescence spectroscopy represents a useful tool in the quantitative evaluation of the radiation exposure and could also be used for the rapid and non-invasive assessment of radiation dose i.e. biodosimeter. The approach is simple, non-invasive and appears to have considerable potential that enables quantitative evaluation of radiation dose exposure in a single hair fiber.

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Specific fluorescent labeling of two functional domains in RNA polymerase α subunit

et al. 1998

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A monomercury derivative of fluoresceine acetate (FMMA) was previously suggested as a specific reagent reacting with only one of four cysteine (Cys) residues in the alpha. subunit of Escherichia coli RNA polymerase. Here, we analyzed the reactivity against FMMA of both isolated alpha subunit and alpha subunit assembled in the holoenzyme. In both cases, the highest reactivity was identified for Cys-269 positioned in the regulatory helix of C-terminal domain (CTD) which includes the contact sites for both class-I transcription factors and DNA UP elements. Substitution of Ala for both Cys-269 and Cys-176 completely eliminates the reactivity of alpha subunit against the fluorescent dye, supporting the prediction that another reactive amino acid under native conformation is Cys-176, which is positioned within or near the region important for alpha dimerization and its binding of beta' subunit. In the isolated alpha subunit, the reactivity against FMMA is different between these two Cys residues and the order is from Cys-269 to Cys-176. Mutant alpha-subunits, bearing only one Cys residue at either 269 or 176, could be reconstituted into locally modified and active enzymes. This FMMA modification system may provide a tool suitable for studies of intra- and intermolecular interactions of this subunit.

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An assay method for disulfide groups by fluorescence quenching

Cited by 128 publications

References 9 publications

Performance Characterization and Optimization of the AgNO₃-Filter/FMA Fluorimetric Method for Atmospheric H₂S Measurements

Performance Characterization and Optimization of the AgNO₃-Filter/FMA Fluorimetric Method for Atmospheric H₂S Measurements

Changes in Human Hair Induced by UV- and Gamma Irradiation

Specific fluorescent labeling of two functional domains in RNA polymerase α subunit

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An assay method for disulfide groups by fluorescence quenching

Cited by 128 publications

References 9 publications

Performance Characterization and Optimization of the AgNO3-Filter/FMA Fluorimetric Method for Atmospheric H2S Measurements

Performance Characterization and Optimization of the AgNO3-Filter/FMA Fluorimetric Method for Atmospheric H2S Measurements

Changes in Human Hair Induced by UV- and Gamma Irradiation

Specific fluorescent labeling of two functional domains in RNA polymerase α subunit

Contact Info

Product

Resources

About

Performance Characterization and Optimization of the AgNO₃-Filter/FMA Fluorimetric Method for Atmospheric H₂S Measurements

Performance Characterization and Optimization of the AgNO₃-Filter/FMA Fluorimetric Method for Atmospheric H₂S Measurements