Origin of the high-frequency resonances in 1H NMR spectra of muscle tissue: an in vitro slow magic-angle spinning study.
High-resolution slow magic-angle spinning (150 Hz) 1H PASS NMR spectroscopy is performed on intact excised rat m. tibialis anterior. Untreated muscles and muscles in vitro incubated in Krebs-Ringers buffer based on deuterium oxide are investigated. In the high-frequency region of the 1H NMR spectra, resonances from H4 (approximately 7.1-7.2 ppm) and H2 (approximately 8.2-8.5 ppm) in histidine are observed. In addition, a resonance appears at 6.7 ppm for the untreated muscles. However, this resonance is absent in muscles following incubation in deuterium oxide. On the basis of its behavior in deuterium oxide combined with supplementary measurements for creatine solutions, the 6.7 ppm resonance is ascribed to the amino protons in creatine. Moreover, the present study demonstrates that the observation of the 6.7 ppm resonance depends on pH, which explains earlier reports stating its occasional appearance. Finally, measurements on solutions of ATP/AMP and histidine indicate that both ATP/AMP and histidine contribute to the resonances at approximately 8.2-8.5 ppm in the 1H NMR spectra of muscle tissue.
Bertram
Hanne Christine
HC
Department of Food Science, Danish Institute of Agricultural Sciences, Research Centre Foulum, P.O. Box 50, DK-8830 Tjele, Denmark. HanneC.Bertram@agrisci.dk
Jakobsen
Hans Jørgen
HJ
Nielsen
Ole Baekgaard
OB
D000255:Adenosine Triphosphate / Q000032:analysis; D000818:Animals; D003401:Creatine / Q000032:analysis; D006639:Histidine / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D018482:Muscle, Skeletal / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D012996:Solutions
D012996:Solutions; D006639:Histidine; D000255:Adenosine Triphosphate; D003401:Creatine