Reconstitution of the sodium channel with partially solubilized lobster nerve membrane.

Reconstitution experiments were carried out with particles obtained from lobster nerve plasma membrane preparations by detergent treatment, differential centrifugation and ammonium sulfate fractionation. The NA channel activity of the three fractions obtained, which have different amounts of the same peptides present in the original membrane, appears related to their content in a large component which does not enter the 9% polyacrylamide gel and in peptides with 220,000 and 110,000 apparent molecular weight. Other reconstitution experiments made with two fractions obtained by detergent treatment, differential centrifugation and gel exclusion chromatography, revealed that the Na channel active fraction contains the material which does not enter the gel in addition to the 220,000 and 110,000 molecular weight peptides. The other fraction was inactive and does not contain those components. The 220,000 dalton peptide has a molecular weight similar to those determined for the tetrodotoxin-saxitoxin receptor and the scorpion toxin receptor of the Na channel. Whether any of the other peptides is a Na channel constituent is unknown at present.