The breakdown and resynthesis of phosphagen in frozen and thawed muscles

Abstract

In frozen frogs'' muscles phosphagen breaks down to inorganic phosphate and creatine, the max. rate of breakdown being at the same temp. ([long dash]2.6[degree] C.) as the max. rate of breakdown of glycogen. Muscles frozen for 24 hrs. not below[long dash]1.5[degree] recover their initial phosphagen content on thawing. Below[long dash]2.5[degree] there is no recovery. Between these temps. recovery is partial, owing to differences in susceptibility to freezing of different fibers. Oxygen is necessary to this recovery process.