title: Determination of p-hydroxyphenylpyruvate, p-hydroxyphenyllactate and tyrosine in normal human plasma by gas chromatography-mass spectrometry isotope-dilution assay.
abstract: The synthesis and purification of [13C2]p-hydroxyphenyllactic acid from [13C2]p-hydroxyphenylpyruvic acid, the characterization of tert.-butyldimethylsilyl-derivatized tyrosine, p-hydroxyphenylpyruvic acid and p-hydroxyphenyllactic acid, and an isotope-dilution assay for these substances in normal human plasma using gas chromatography-mass spectrometry (GC-MS) are described. Using this method plasma p-hydroxyphenylpyruvate, p-hydroxyphenyllactate and tyrosine levels of 68 +/- 42 ng/ml, 118 +/- 45 ng/ml and 16.6 +/- 6.3 micrograms/ml, respectively, were found in 9 normal adults. Isotope-dilution assays are sensitive enough to determine tyrosine, p-hydroxyphenylpyruvate and p-hydroxyphenyllactate content in normal subjects, and may be useful for studying disorders of tyrosine metabolism, including inborn errors of metabolism, liver disease and ascorbic acid deficiencies.
authors.affiliation: University of Colorado Health Sciences Center, Denver 80220, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Deutsch
mesh_terms: D002247:Carbon Isotopes; D003903:Deuterium; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007201:Indicator Dilution Techniques; D010666:Phenylpropionates / Q000097:blood*; D010667:Phenylpyruvic Acids / Q000097:blood*; D014443:Tyrosine / Q000097:blood*
chemical_list: D002247:Carbon Isotopes; D010666:Phenylpropionates; D010667:Phenylpyruvic Acids; C010590:4-hydroxyphenylpyruvic acid; C001418:4-hydroxyphenyllactic acid; D014443:Tyrosine; D003903:Deuterium