title: Simultaneous determination of plasma total homocysteine and methionine by liquid chromatography-tandem mass spectrometry.
abstract: The sulfur-containing amino acid homocysteine is a cardiac risk factor and a biomarker for several inborn errors of metabolism in methionine synthesis. A simple LC-MS/MS method was developed and validated for determination of homocysteine and methionine in human plasma. Rapid separation was achieved using a reverse phase liquid chromatography. Mass spectrometry identification was performed in positive electrospray ionization mode for homocysteine and methionine. Accuracy, precision, linearity, recovery and sample stability were evaluated in the method validation. The test is applied in diagnosis of homocystinuria and monitoring total homocysteine levels. Moreover, simultaneous measurement of methionine helps in the differentiation of homocystinuria and some cobalamin disorders (such as cblC and cblD defects) without additional amino acid testing. Lastly, this assay is sensitive to detect reduced total homocysteine levels that are possibly seen in sulfocysteinuria and molybdenum cofactor deficiencies.
authors.affiliation: Division of Biochemical Genetics, Baylor Genetics, Houston, TX, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Division of Biochemical Genetics, Baylor Genetics, Houston, TX, United States.
authors.forename: Brandon
authors.initials: B
authors.lastname: Mistretta
authors.affiliation: Division of Biochemical Genetics, Baylor Genetics, Houston, TX, United States; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.
authors.forename: Sarah
authors.initials: S
authors.lastname: Elsea
authors.affiliation: Division of Biochemical Genetics, Baylor Genetics, Houston, TX, United States; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States. Electronic address: qsun@bcm.edu.
authors.forename: Qin
authors.initials: Q
authors.lastname: Sun
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods*; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D057230:Limit of Detection; D016014:Linear Models; D008715:Methionine / Q000097:blood*; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013997:Time Factors
chemical_list: D006710:Homocysteine; D008715:Methionine
keywords: Homocysteine; Homocystinuria; Methionine; Sulfocysteinuria; Tandem mass spectrometry; cblC