N-acetylated metabolites in urine: proton nuclear magnetic resonance spectroscopic study on patients with inborn errors of metabolism.
BACKGROUND
There is no comprehensive analytical technique to analyze N-acetylated metabolites in urine. Many of these compounds are involved in inborn errors of metabolism. In the present study, we examined the potential of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy as a tool to identify and quantify N-acetylated metabolites in urine of patients with various inborn errors of metabolism.


METHODS
We performed (1)H-NMR spectroscopy on a 500 MHz spectrometer. Using a combination of one- and two-dimensional correlation spectroscopy (COSY) (1)H-NMR spectra, we were able to assign and quantify resonances of characteristic N-acetylated compounds products in urine of patients with 13 inborn errors of metabolism.


RESULTS
The disease-specific N-acetylated metabolites were excreted at concentrations >100 micromol/mmol of creatinine in the patients' urine. In control urine samples, the concentration of individual N-acetyl-containing compounds was <40 micromol/mmol of creatinine. The combination of one- and two-dimensional COSY NMR spectroscopy led to the correct diagnosis of nine different inborn errors of metabolism. No abnormalities were observed in the spectra of urine from patients with G(M1)- or G(M2)-gangliosidosis. We also determined the (1)H-NMR characteristics of N-acetylated metabolites that may be relevant to human metabolism.


CONCLUSIONS
(1)H-NMR spectroscopy may be used to identify and quantify N-acetylated metabolites of diagnostic importance for the field of inborn errors of metabolism.
Engelke
Udo F H
UF
University Medical Center Nijmegen, Laboratory of Pediatrics and Neurology, NL-6500 HB Nijmegen, The Netherlands.
Liebrand-van Sambeek
Maria L F
ML
de Jong
Jan G N
JG
Leroy
Jules G
JG
Morava
Eva
E
Smeitink
Jan A M
JA
Wevers
Ron A
RA
D000085:Acetates / Q000737:chemistry*; D000107:Acetylation; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008661:Metabolism, Inborn Errors / Q000378:metabolism* / Q000652:urine*; D008875:Middle Aged
D000085:Acetates