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标题：A new LC-MS assay for the quantitative analysis of vitamin K metabolites in human urine
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作者：Matthew G. McDonald ; Catherine K. Yeung ; Matthew G. McDonald 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2019
卷号：60
期号：4
页码：892-899
DOI：10.1194/jlr.D087916
出版社：American Society for Biochemistry and Molecular Biology
摘要：Vitamin K (VK), in both its phylloquinone and menaquinone forms, has been hypothesized to undergo ω- and β-oxidation on its hydrophobic side chain in order to generate the observed urinary metabolites, K acid I and K acid II, which are excreted primarily as glucuronide conjugates. Synthetic standards of K acid I, K acid II, and a putative intermediate metabolite, menaquinone (MK)1 ω-COOH, were used to develop and optimize a new atmospheric pressure negative chemical ionization LC-MS/MS assay for the quantitation of these compounds in urine from untreated individuals and subjects treated with a high dose VK supplement. VK catabolites were extracted from urine, deconjugated, and converted to their methyl ester derivatives using previously reported methodology. The assay showed a high degree of sensitivity, with limits of detection below 10–50 fmol of metabolite per milliliter of urine, as well as an inter-assay precision of 8–12%. Metabolite standards provided unambiguous evidence for MK1 ω-COOH as a new human urinary metabolite of VK. This assay provides a minimally invasive, highly sensitive, and specific alternative for monitoring VK status in humans..
关键词：beta;oxidation ; omega;oxidation ; liquid chromatography;mass spectrometry ; menaquinone ; phylloquinone