Cysteine Sulfinic Acid in the Central Nervous System: Specific Binding of [35S]Cysteic Acid to Cortical Synaptic Membranes-An Investigation of Possible Binding Sites for Cysteine Sulfinic Acid
Article first published online: 5 OCT 2006
Journal of Neurochemistry
Volume 38, Issue 5, pages 1275–1279, May 1982
How to Cite
Iwata, H., Yamagami, S. and Baba, A. (1982), Cysteine Sulfinic Acid in the Central Nervous System: Specific Binding of [35S]Cysteic Acid to Cortical Synaptic Membranes-An Investigation of Possible Binding Sites for Cysteine Sulfinic Acid. Journal of Neurochemistry, 38: 1275–1279. doi: 10.1111/j.1471-4159.1982.tb07901.x
- Issue published online: 5 OCT 2006
- Article first published online: 5 OCT 2006
- Received June 10, 1981; revised September 28, 1981; accepted November 6, 1981.
- Cysteine sulfinic acid;
- Cysteic acid;
- Excitatory amino acid
Abstract: Specific binding sites for cysteine sulfinic acid, an excitatory amino acid, in crude synaptic membrane fractions of rat cerebral cortex were examined, using L-[35S]cysteic acid as a ligand. Two specific binding systems of [35S] cystec acid were found, one Na+-dependent and the other Na+-independent. The Na+-independent specific binding of [35S]Cysteic acid was saturable, with a Kd of 474 nM and Bmax of 3.29 pmol/mg protein. The binding was optimal at pH 7.4 and at 37°C. Treatment of the membranes with proteases, concanavalin A, or Triton X-100 markedly reduced the binding. Of various compounds related to cysteic acid, L-cysteine sulfinic acid was the most effective competitor of this binding. These results indicate the existence of an Na+-independent specific binding site for cysteic acid in the synaptic membrane of rat cerebral cortex, which may be different from that for glutamate. Possible involvement of cysteine sulfinic acid as an endogenous ligand for this binding site is discussed.