Range: ±1 Table - link kJ/mol
||Human Homo sapiens
||Wackerhage, H. et al. Recovery of free ADP, Pi, and free energy of ATP hydrolysis in human skeletal muscle. J Appl Physiol (85):2140-2145. 1998. p.2143 table 1PubMed ID9843537
||31P-NMR. (Nuclear Magnetic Resonance). The natural form of phosphorus (31P) has magnetic properties, so there is no need to add any substance in order to obtain results from the spectrometer. The tissue such as muscle is placed in a strong magnetic field and shifts in frequency of radiofrequency pulses are used to infer concentration of ATP and Pi directly from the peaks on the NMR spectra (Ron Milo). ?GATP is assumed to match the free energy of PCr (Phosphocreatine) hydrolysis.
||"Calculated free [ADP] decreased significantly below its initial resting concentration in the 50% TF [test force] test but not in the 20% TF test (Fig. 7, Table 1). The undershoots of both [Pi] and free [ADP] resulted in an undershoot of ?GATP (Fig. 8, Table 1)." "Undershoots of free [ADP], [Pi], and ?GATP below their initial resting concentrations: Undershoots of [Pi] after exercise (Fig. 5, Table 1) were also measured in other 31P-NMR studies (e.g., see Ref. 4). The most likely explanation is that Pi was temporarily bound in glycolytic sugar phosphates, which appear as a separate PME [phosphomonoester] peak in a high-field-strength 31P-NMR spectrum during and after intensive exercise (ref 4)." This study was done on endurance-trained athletes. The change in free energy due to ATP hydrolysis of resting muscle in non-athletes is likely to have a slightly lower absolute value.