Size characteristics of the solubilized saxitoxin receptor of the voltage-sensitive sodium channel from rat brain.

The saxitoxin receptor of the voltage-sensitive sodium channel from rat brain was solubilized with Triton X-100 and stabilized with phosphatidylcholine. The size characteristics of the detergent . phospholipid . receptor complex were studied by gel filtration and sucrose gradient sedimentation in H2O and D2O. The complex has Stokes radius = 80 A, S20,W = 12 S, v = 0.82 ml/ g, and Mr = 601,000 +/- 48,000. Assuming v = 0.73 ml/g for the saxitoxin receptor protein, the mass of the complex consists of 47.4% detergent and phosphatidylcholine and 52.6% saxitoxin receptor protein with Mr = 316,000 +/- 63,000.