Ion-Exchange High Performance Liquid Chromatographic Determination of Selenomethionine by Reaction with Cyanogen Bromide

Wolf, Wayne R.; Lacroix, Denis; Slagt, M. E.

doi:10.1080/00032719208020083

Cited by 14 publications

(7 citation statements)

References 6 publications

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“…An ion-exchange high-pressure liquid chromatography (LC) technique based on the well known reaction of methionine (Met) with cyanogen bromide (CNBr) [1] was utilized to accurately determine selenomethionine (SeMet) in biochemical samples [2]. In that study the [2].…”

Section: Introductionmentioning

confidence: 99%

Utilization of Chromatographic and spectroscopic techniques to study the oxidation kinetics of selenomethionine

Zainal

Lacroix

Wolf

1996

Fresenius J Anal Chem

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Ion-exchange LC and spectroscopic supporting techniques have been successfully used to study the kinetics and mechanism of oxidation reactions of selenomethionine (SeMet). Oxidation of selenomethionine with both cyanogen bromide (CNBr) and hydrogen peroxide (H(2)O(2)) proceeds through a stable intermediate which undergoes cyclization and C-Se bond cleavage to form 2-amino-4-butyrolactone. This stable intermediate was identified by IR spectroscopy as methionine dihydroxy selenide. The CH(3)-Se moiety of SeMet formed methyl selenic acid upon reaction with H(2)O(2) and methyl selenocyanate (CH(3)SeCN), characterized by GC-MS, for the reaction with CNBr. Both reactions were of apparent first order with respect to the concentration of SeMet. A rate constant (k(1))of 4.0x10(-3) s(-1) for the reaction of SeMet with HO and 4.0x10(-3) s(-1) for the reaction with CNBr were determined at a temperature of 22 degrees C. Oxidation of methionine (Met) gives disparate kinetics and oxidation products from SeMet. Thus the differential rate method can be utilized to quantitatively separate SeMet in biological samples in the presence of much higher concentrations of Met.

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Section: Introductionmentioning

confidence: 99%

Utilization of Chromatographic and spectroscopic techniques to study the oxidation kinetics of selenomethionine

Zainal

Lacroix

Wolf

1996

Fresenius J Anal Chem

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“…HPLC analysis of amino acids in wheat gluten. The HPLC apparatus, conditions of amino acid separation, and postcolumn derivatization have been described previously (27). HPLC…”

Section: Methodsmentioning

confidence: 99%

Optimization of an Escherichia coli formate dehydrogenase assay for selenium compounds

Tschursin

Wolf

Lacroix

et al. 1994

Appl Environ Microbiol

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A microbiological assay to detect different chemical compounds of selenium for potential future use in the study of the distribution of these chemical forms in foods is being developed. This assay is based on the detection, by infrared analysis, of CO2 in a culture of Escherichia coli when the bacteria are grown in the presence of various selenium compounds. The CO2 production is the result of selenium-dependent formate dehydrogenase activity, which catalyzes oxidation of formic acid produced during glucose metabolism. Smooth response curves were generated over several orders of magnitude for selenocystine, selenite, and selenomethionine. The assay detects selenium concentrations (above background) as low as 1.5 nM for selenocystine and selenite and 4 nM for selenomethionine in minimal medium. Detection of selenomethionine was enhanced (to a sensitivity of 1.5 nM) by the addition of methionine to minimal medium and was enhanced even further (to a sensitivity of 0.8 nM) by the addition of a defined mixture of amino acids. Selenomethionine could be assayed in the presence of an amino acid concentration which is proportional to the amino acid/elemental selenium ratio found in a wheat gluten reference material (NIST SRM 8418). This implies that the assay can detect selenium compounds in a variety of foods at low concentrations, avoiding the background CO2 production caused by high concentrations of non-selenium-containing amino acids. The observation that methionine enhanced selenomethionine availability for formate dehydrogenase synthesis supports studies in animals demonstrating that methionine controls selenomethionine incorporation into selenoenzymes. Although determination of selenium by isotope dilution-mass spectrometry is more sensitive for detecting elemental selenium in biological materials, the microbiological assay detects metabolically utilized selenium, which is currently of interest in nutrition research.

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“…The combination of this detection method with ion-exchange HPLC has been examined and a calibration curve obtained over a dynamic range of 30-500 nM selenomethionine. 55 In recent years mixtures of amino acids have been analysed by reversed-phase liquid chromatography. 56 Presumably this technique will also encompass any selenoamino acids or small peptides that might be included in extracts or digests.…”

Section: Plantsmentioning

confidence: 99%

The identification of selenium species in biological samples

Edmonds

Morita

2000

Appl. Organometal. Chem.

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Ion-Exchange High Performance Liquid Chromatographic Determination of Selenomethionine by Reaction with Cyanogen Bromide

Cited by 14 publications

References 6 publications

Utilization of Chromatographic and spectroscopic techniques to study the oxidation kinetics of selenomethionine

Utilization of Chromatographic and spectroscopic techniques to study the oxidation kinetics of selenomethionine

Optimization of an Escherichia coli formate dehydrogenase assay for selenium compounds

The identification of selenium species in biological samples

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