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Biochemical characterization of plasma membrane isolated from human skeletal muscle
Author(s) -
Desnuelle C.,
Liot D.,
Serratrice G.,
Lombet A.
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)80376-8
Subject(s) - ouabain , chemistry , receptor , membrane , population , antagonist , phosphatase , affinities , biochemistry , biophysics , enzyme , biology , sodium , demography , organic chemistry , sociology
Specific components of ion translocation systems were studied in excitable plasma membranes isolated from normal human muscle. Na + ‐ K + ATPase and ouabain‐sensitive K + phosphatase activities were 8.9 ± 1 per mg protein and 96 ± 9 per mg protein, respectively. Scatchard analysis of equilibrium binding assays with [ 3 H]ouabain showed non‐linear curves consistent with high‐ and low‐affinity sites (estimated K d 3 nM and 0.22 μM). Two families of receptors with different affinities for a tritiated TTX derivative (estimated K d 0.4 and 4 nM) were also identified suggesting the existence in human muscle of at least two classes of voltage‐dependent Na + channels. In addition (+)‐[ methyl ‐ 3 H]PN200‐110, a potent Ca 2+ antagonist used for labeling voltage‐dependent Ca 2+ channels, was observed to bind to a homogeneous population of receptors in the plasma membrane ( K d = 0.2 nM).