title: Class selection of amino acid metabolites in body fluids using chemical derivatization and their enhanced 13C NMR.
abstract: We report a chemical derivatization method that selects a class of metabolites from a complex mixture and enhances their detection by 13C NMR. Acetylation of amines directly in aqueous medium with 1,1'-13C(2) acetic anhydride is a simple method that creates a high sensitivity and quantitative label in complex biofluids with minimal sample pretreatment. Detection using either 1D or 2D 13C NMR experiments produces highly resolved spectra with improved sensitivity. Experiments to identify and compare amino acids and related metabolites in normal human urine and serum samples as well as in urine from patients with the inborn errors of metabolism tyrosinemia type II, argininosuccinic aciduria, homocystinuria, and phenylketonuria demonstrate the method. The use of metabolite derivatization and 13C NMR spectroscopy produces data suitable for metabolite profiling analysis of biofluids on a time scale that allows routine use. Extension of this approach to enhance the NMR detection of other classes of metabolites has also been accomplished. The improved detection of low-concentration metabolites shown here creates opportunities to improve the understanding of the biological processes and develop improved disease detection methodologies.
authors.affiliation: Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA.
authors.forename: Narasimhamurthy
authors.initials: N
authors.lastname: Shanaiah
authors.forename: M Aruni
authors.initials: MA
authors.lastname: Desilva
authors.forename: G A
authors.initials: GA
authors.lastname: Nagana Gowda
authors.forename: Michael A
authors.initials: MA
authors.lastname: Raftery
authors.forename: Bryan E
authors.initials: BE
authors.lastname: Hainline
authors.forename: Daniel
authors.initials: D
authors.lastname: Raftery
mesh_terms: D000596:Amino Acids / Q000097:blood* / Q000145:classification / Q000652:urine*; D001125:Argininosuccinic Acid / Q000652:urine; D002247:Carbon Isotopes; D006712:Homocystinuria / Q000097:blood / Q000175:diagnosis / Q000652:urine; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D010661:Phenylketonurias / Q000097:blood / Q000175:diagnosis / Q000652:urine; D014443:Tyrosine / Q000097:blood / Q000652:urine
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D001125:Argininosuccinic Acid; D014443:Tyrosine