title: Determination of amino acid enantiomers in human urine and blood serum by gas chromatography-mass spectrometry.
abstract: Amino acid (AA) enantiomers were determined as N(O)-pentafluoropropionyl-(2)-propyl esters by chiral gas chromatography-mass spectrometry (GC-MS) in 24 h samples of the urine of three healthy volunteers and in their blood sera. In urine the largest amounts were determined for D-Ser (64-199 micromol/day) and D-Ala (24-138 micromol/day). In blood sera, D-Ala (2.3-4.2 micromol/L) and D-Ser (1.0-2.9 micromol/L) were most abundant. Varying amounts of the D-enantiomers of Thr, Pro, Asx, Glx, Phe, Tyr, Orn and Lys were also found, albeit not in all urines and sera. Further, enantiomers were quantified in urine samples of two volunteers fasting for 115 h. Quantities of renally excreted D-AAs decreased in fasting, although amounts of D-Ser (69 and 77 micromol/L urine) as well as other D-AAs were still detectable. Time-dependent analyses of urine showed that D-AAs are continuously excreted.
authors.affiliation: Department of Food Sciences, Institute of Nutritional Science, Interdisciplinary Research Center, Justus-Liebig-University of Giessen, 35392 Giessen, Germany. hans.brueckner@ernaehrung.uni-giessen.de
authors.forename: H
authors.initials: H
authors.lastname: Brückner
authors.forename: A
authors.initials: A
authors.lastname: Schieber
mesh_terms: D000596:Amino Acids / Q000097:blood* / Q000652:urine*; D005215:Fasting; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008894:Milk Proteins / Q000008:administration & dosage; D012016:Reference Values; D013237:Stereoisomerism; D015014:Yogurt
chemical_list: D000596:Amino Acids; D008894:Milk Proteins