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Solubilization and Characterization of Opioid Binding Sites from Frog ( Rana esculenta ) Brain
Author(s) -
Simon J.,
Szücs M.,
Benyhe S.,
Borsodi A.,
Zeman P.,
Wollemann M.
Publication year - 1984
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1984.tb12830.x
Subject(s) - digitonin , receptor , solubilization , membrane , chemistry , stereospecificity , rana , enkephalin , binding site , biochemistry , biophysics , chromatography , stereochemistry , biology , opioid , endocrinology , catalysis
Abstract: Active opioid receptors were solubilized from frog ( Rana esculenta ) brain membrane fractions by the use of 1% digitonin. It was found by kinetic as well as by equilibrium measurements that both the membrane and the solubilized fractions contain two binding sites. For the membrane preparations, K D values were 0.9 and 3.6 n M , and B max values were 293 and 734 fmol/mg protein. For the solubilized preparations, K D values were 0.4 and 2.6 n M , and B max values were 35 and 266 fmol/mg protein. The stereospecificity of the binding did not change during solubilization. Both the membrane‐bound and the solubilized receptors showed weak binding of enkephalin and μ‐specific drugs, suggesting that they are predominantly of the k ‐type. The membrane‐bound and the soluble receptors showed the same distribution of subtypes, i.e., 70% k , 13%μ, and 17%δ for the membrane‐bound and 71% k , 17%μ, and 12%δ for the soluble receptors