Cellular and Molecular Changes Necessary for Preparation of Sarcolemma From Chicken Skeletal Muscle at Low Ionic Strength

Emptying of homogenized segments of skeletal muscle cells in solutions of low ionic strength was directly related to actomyosin content and inversely to content of nucleotide pyrophosphate. Segments from muscle which had undergone thaw rigor, had low nucleotide pyrophosphate and high actomyosin content but did not empty. Glycerinated muscle cell segments, which also had low nucleotide pyrophosphate and high actomyosin contents, were incapable of emptying until the Z‐line was extracted. Treatment with ATP, which dissociated actomyosin, prevented emptying even after the Z‐line had been removed. It is concluded that both actomyosin formation and Z‐line disintegration are required before emptying of muscle cell segments will occur.