PT  - JOURNAL ARTICLE
AU  - Strichartz, G
TI  - Structure of the saxitoxin binding site at sodium channels in nerve membranes. Exchange of tritium from bound toxin molecules.
DP  - 1982 Mar 01
TA  - Molecular Pharmacology
PG  - 343--350
VI  - 21
IP  - 2
4099  - http://molpharm.aspetjournals.org/content/21/2/343.short
4100  - http://molpharm.aspetjournals.org/content/21/2/343.full
SO  - Mol Pharmacol1982 Mar 01; 21
AB  - The exchange of tritium into water from saxitoxin molecules that were radiolabeled at the C-11 methylene position was measured at 37 degrees in solution and in suspensions of brain membranes. High concentrations of membrane receptors were used to assure that more than 80% of the total saxitoxin (STX) present was specifically bound. The amount of back-exchanged tritium was determined either by measuring the radioactivity remaining in the STX, using a second binding assay, or by measuring the tritium in water using ion-exchange chromatography. The results show that the back-exchange is accelerated in the presence of the membranes, and that this is attributable solely to the nonspecific toxin binding. Little change in the back-exchange rate over that in solution occurs in specifically bound toxin molecules. These results place certain restrictions on the possible bonds and configurations of receptor-toxin complexes.