Solubilization of Kainic Acid Binding Sites from Rat Brain

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Abstract
Kainic acid binding sites were solubilized from rat brain using a combination of Triton X-100 and digitonin. The highest percentage of solubilized binding sites (45%) was obtained by treating brain membranes with 1% Triton-X-100 and digitonin in 0.5 M potassium phosphate containing 20% glycerol. The solubilized binding sites were stable and amendable to analysis by gel filtration and lectin affinity chromatography. Computer assisted analyses demonstrated that the solubilized sites displayed high- and low-affinity binding constants similar to the membrane-bound sites. Competition experiments further supported the pharmacological similarities of the solubilized and membrane-bound sites. Gel filtration chromatography of the solubilized binding site indicated that the detergent-bound complex had a Stokes radius of 82.7 .ANG.. The [3H]kainic acid binding site appears to be glycosylated based on its capability to bind to lectins. The lectin, wheatgerm agglutinin, proved to be potentially useful tool for characterization because the solubilized binding sites were bound and eluted in relatively high yield.