Identification of 4-methoxybenzoyl-N-glycine in urine by gas chromatography/mass spectrometry.

An unusual metabolite was detected in the urine of two children with neurological dysfunctions of unclear aetiology by using gas chromatography/mass spectrometry (GC/MS). On the basis of the analysis of its fragmentation pathways, synthesis of tentative compound and its GC/MS analysis it was stated that the unknown metabolite is 4-methoxybenzoyl-N-glycine.

Discovery of methoxyacetylcarbamide in the urine of normal adults and phenylketonuric children.

In order to study metabolic distinctions in phenylketonuria, urinary metabolites in the form of trimethylsilyl derivatives have been characterized by high resolution gas chromatography and mass spectrometry. A previously unknown metabolite has been found in the urine of some untreated phenylketonuric infants between 2 and 5 yr of age. The metabolite was absent in healthy children of the same age. The metabolite appeared to be present in the urine of apparently healthy adults (25-32 yr old). The metabolite was identified as methoxyacetylcarbamide on the basis of mass fragmentation analysis and compared with synthetic methoxyacetylcarbamide. Their retention times and mass spectra coincided.

Determination of human fibroblasts metabolism in vitro by gas chromatography-mass spectrometry of cell-excreted metabolites.

In order to develop an approach to the study of cell metabolism in vitro, we undertook the determination of metabolites excreted by human skin diploid fibroblasts into culture medium using high-resolution gas chromatography in combination with mass spectrometry. Chromatographic and mass spectrometric characteristics of 29 metabolites have been obtained, and 11 of the metabolites have been identified. The excreted metabolites reflect the activity of certain metabolic processes in fibroblasts in vitro. A comparison of chromatographic and mass spectrometric characteristics of the cell metabolites and of those excreted from the body in urine showed most of the metabolites excreted by fibroblasts to be different from the urine metabolites. The possibility of secondary conversion of cell metabolites in the organism and the specificity of metabolism in cells of different tissues are discussed.

Excretion of phenylpyruvic, 4-hydroxyphenylpyruvic and indolyl-3-acetic acids by the skin fibroblasts from a phenylketonuric child.

High-resolution gas chromatography and mass spectrometry have been used to analyse the changing chemical composition of the culture medium upon the growth of skin fibroblasts from a healthy individual and from a classical phenylketonuric (PKU) patient. The PKU fibroblasts, unlike normal ones, were found to excrete into the culture medium phenylpyruvate, 4-hydroxyphenylpyruvate, indolyl-3-acetate and an unidentified metabolite containing the phenyl group. This testifies to the disturbed metabolism of phenylalanine, tyrosine and tryptophan in the PKU fibroblasts. This seems to be the reason for their reduced viability as compared with normal fibroblasts.