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The enzyme activity in a detergent-treated sarcolemma of skeletal muscles

1970; Elsevier BV; Volume: 219; Issue: 2 Linguagem: Inglês

10.1016/0005-2736(70)90214-2

1879-2642

D. L. Ferdman, Nastassja Himmelreich, G.P. Dyadyusha,

thermodynamics and calorimetric analyses

From rabbit skeletal muscles, a fraction of plasma membrane sarcolemma was isolated. The sarcolemma was treated with nonionic and anionic detergents. Investigations resulted in the following conclusions: 1. 0.1% solution of Triton X-100 separates off from the sarcolemma 25–33% of the protein, which is almost completely sedimented by ultracentrifugation at 105 000 × g. 80–85% of the phospholipids remain in the ultracentrifugate. Thus, both in the sarcolemma and its fragments, following treatment with Triton X-100, the phospholipid content is greatly reduced. The specific activity of ATPase (EC 3.6.1.3), acetylcholinesterase (EC 3.1.1.7) and AMP-aminohydrolase (EC 3.5.4.6), after treatment of sarcolemma with Triton X-100, undergoes no changes. 2. 0.5% solution of sodium deoxycholate separates off 60–70% of the sarcolemma protein, most of which is not sedimented by ultracentrifugation. Just as after treatment with Triton X-100, the main part of the phospholipids remains in the ultracentrifugate. 0.5% solution of sodium deoxycholate has an inactivating effect both on ATPase and AMP aminohydrolase. The activity of sarcolemma acetylcholinesterase after treatment with sodium deoxycholate becomes substantially increased. 3. Sodium dodecyl sulfate at a concentration of 0.001% separates off from the sarcolemma 30–40% of the protein, which is almost entirely sedimented by ultracentrifugation at 105 000 × g. Corresponding to this amount a distribution of phospholipids takes place. Acetylcholinesterase and AMP aminohydrolase after treatment with sodium dodecyl sulfate are mainly accumulated in the fraction sedimented at 5000 × g. A part of the ATPase activity becomes transferred to the fraction sedimented by ultracentrifugation, with an increase in its specific activity.