Synthesis of [guanidino-13C]creatine and measurement of the creatine phosphokinase reaction in vitro by 13C NMR spectroscopy.
Magnetic resonance in medicine
confidence
Key findings
Synthesis of [guanidino-13C]creatine and measurement of creatine phosphokinase reaction in vitro by 13C NMR; determined Km = 15.5 mM.
View source on PubMed (PMID 3747823) ↗
- Sample size
- N/A
- Population
- In vitro creatine phosphokinase reaction
- Dosing
- N/A
- Duration
- N/A
- Route
- N/A
- Blinding
- not_reported
- Controls
- none
- Drug class
- nootropic
Full abstract
[guanidino-13C]Creatine has been synthesized by reaction involving synthesis of [13C]cyanamide followed by its condensation with sarcosine. The creatine guanidino carbon 13C NMR frequency shifts upon the formation of phosphocreatine by 0.83 ppm with a splitting (2JCP = 3.3 Hz) due to two-bond phosphorus-carbon coupling. The high 13C enrichment (99%) at the guanidino carbon of creatine gave rise to an adequate signal-to-noise ratio for both creatine and phosphocreatine so that a study of the time course of the creatine phosphokinase reaction could be performed and provided the means for a determination of the Km (15.5 mM) of the reaction.