title: The separation of phosphocreatine from creatine, and pH determination in frog muscle by natural abundance 13C-NMR.
abstract: Phosphocreatine can be separated from creatine in superfused frog muscle by natural abundance 13C-NMR, based on the difference in resonance frequency of their guanidino carbons. After taking into account the longitudinal relaxation times and nuclear Overhauser enhancement factors, the integrated peak areas of the guanidino carbons could be used for determination of the phosphocreatine-to-creatine ratio in the muscle. The pH dependence of the chemical shift of the C-2 carbon in the histidine ring of carnosine was used for estimation of the intracellular pH in the intact muscle.
mesh_terms: D000818:Animals; D002247:Carbon Isotopes; D003401:Creatine / Q000032:analysis*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009132:Muscles / Q000032:analysis*; D010725:Phosphocreatine / Q000032:analysis*; D011894:Rana pipiens
chemical_list: D002247:Carbon Isotopes; D010725:Phosphocreatine; D003401:Creatine