title: T-system membranes in microsomal fractions of crayfish muscles: identification and differences in protein composition.
abstract: Specific binding of 3H-ouabain and ruthenium red (RR) to membranes of T-tubules in crayfish muscles was used to identify the subfraction containing vesicles originating from the T-system. The microsomal fraction was prepared by differential centrifugation, and subfractions were separated in continuous or discontinuous sucrose density gradients. 3H-ouabain binding was estimated by scintillation counting; RR binding was examined by electron microscopy. The light subfraction was identified using both methods as that containing vesicles of T-tubules. Protein separation by SDS-electrophoresis revealed marked differences between the subfraction containing vesicles of T-tubules and other subfractions, the most distinctive feature being the presence of a protein of Mr 46,000 predominantly in the light subfraction.
mesh_terms: D000818:Animals; D003400:Astacoidea / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D008566:Membranes / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism*; D008870:Microtubules / Q000648:ultrastructure; D009124:Muscle Proteins / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D010042:Ouabain; D012430:Ruthenium Red; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D009124:Muscle Proteins; D012430:Ruthenium Red; D010042:Ouabain