Assay of the human liver citric acid cycle probe phenylacetylglutamine and of phenylacetate in plasma by gas chromatography-mass spectrometry.
Assay of the human liver citric acid cycle probe phenylacetylglutamine and of phenylacetate in plasma by gas chromatography-mass spectrometry.
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DOI：
10.1006/abio.1993.1323
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发表时间：
1993-07
影响因子：
2.9
通讯作者：
D. Yang;M. Beylot;K. C. Agarwal;M. Soloviev;H. Brunengraber
中科院分区：
文献类型：
--
作者：
D. Yang;M. Beylot;K. C. Agarwal;M. Soloviev;H. Brunengraber
苯乙酸衍生自苯丙氨酸，在人类和灵长类动物肝脏中转化为苯乙酰谷氨酰胺。后者已被用来评估肝脏柠檬酸循环中间体的标记模式。我们提出了气相色谱-质谱法测定苯乙酰谷氨酰胺，苯乙酸，苯丙氨酸在生物体液中。化合物用二甲基甲酰胺二甲基缩醛衍生化。苯乙酰谷氨酰胺和苯乙酸的检测限为0.1 nmol，苯丙氨酸的检测限为2 nmol。苯乙酸和苯乙酰谷氨酰胺的基线血浆浓度分别为1和3 μ M。苯乙酸和苯乙酰谷氨酰胺的24小时尿排泄量分别约为4 μ mol和1 mmol。人摄入苯丙氨酸（以苯丙氨酸甲酯的形式）后，血浆和尿液中苯乙酸盐和苯乙酰谷氨酰胺浓度依次增加。该检测开辟了一条途径，以非侵入性探测的13 C-标记模式的肝脏柠檬酸循环中间体在人类。
Phenylacetate, derived from phenylalanine, is converted in human and primate liver to phenylacetylglutamine. The latter has been used to assess the labeling pattern of liver citric acid cycle intermediates. We present gas chromatographic-mass spectrometric assays of phenylacetylglutamine, phenylacetate, and phenylalanine in biological fluids. The compounds are derivatized with dimethylformamide dimethyl acetal. Limits of detection are 0.1 nmol for phenylacetylglutamine and phenylacetate and 2 nmol for phenylalanine. Baseline plasma concentrations of phenylacetate and phenylacetylglutamine and 1 and 3 microM, respectively. The 24-h urinary excretions of phenylacetate and phenylacetylglutamine are about 4 mumol and 1 mmol, respectively. Ingestion of phenylalanine (in the form of aspartame) by a human is followed by sequential increases in phenylacetate and phenylacetylglutamine concentrations in plasma and urine. This assay opens the way to noninvasive probing of the 13C-labeling pattern of liver citric acid cycle intermediates in humans.