作者: M. Rosemblatt , C. Hidalgo , C. Vergara , N. Ikemoto
DOI: 10.1016/S0021-9258(18)43399-6
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摘要: A new method for isolating transverse tubule membranes from rabbit skeletal muscle has been developed. This procedure the advantage of being mild, fast, and producing with good yields a purified membrane fraction. The are by discontinuous sucrose density centrifugation after loading contaminating light sarcoplasmic reticulum vesicles calcium phosphate in presence ATP. Immunofluorescence staining cryostat sections psoas goat antibodies directed against shows that reacting antigens distributed at boundary I bands myofibrils where tubules localized mammalian muscle. showed no cross-reactivity reticulum, nor did they show any fluorescence plasma membrane, indicating isolated indeed originate tubules. fraction characteristic protein composition distinguishable much higher cholesterol content than crude microsomes, phospholipid about twice as high membrane. distinct contents sphingomyelin phosphatidylserine. Mg2+-activated ATPase undergoes 20-30-fold increase specific activity during purification. levels Ca2+-ATPase present remain comparable to those even extensive removal latter.