Actomyosin chemical mechanisms

In the most recent work, Dawson et al (1978) have extended their muscle NMR studies to investigate the biochemical factors affecting muscular fatigue. The substances most directly involved in the transduction of chemical free energy into mechanical work in contracting muscle are ATP, ADP, Pi, H, and Mg all of these substances actually take part in the actomyosin-ATPase reactions which produce contraction. PCr is also involved in normal contractions of vertebrate muscles because the ATP that is hydrolyzed is rapidly rephosphorylated at the expense of PCr by the enzyme creatine phosphotransferase. Since P NMR can monitor all of these substances simultaneously, either directly or indirectly, it becomes possible to relate changes in them to concurrent changes in the mechanical performance of muscles. 

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