title: [The nature of cation-binding groups in binding sites for [[3H]Tyr1, D-Ala2, D-Leu5]enkephalin].
abstract: The influence of pH on binding of labeled stable analog of enkephalin, [3H]Tyr1, D-Ala2, D-Leu5]enkephalin, to high- and low-affinity receptors of rat brain membranes was studied. It was shown that alkali-earth metal ions combine with a deprotonated group (pKa 7,0) of the high-affinity receptor, thereby activating the latter. The effect of cations on the low-affinity enkephalin binding is independent of pH. The presence of phosphate group in the high-affinity binding site, as well as of imidazole residue in the low-affinity binding site was surmised. The latter supposition was supported by data on chemical modification of the membrane preparation with the aid of diethylpyrocarbonate.
authors.forename: S V
authors.initials: SV
authors.lastname: Zaĭtsev
authors.forename: N V
authors.initials: NV
authors.lastname: Porodenko
authors.forename: S D
authors.initials: SD
authors.lastname: Varfolomeev
mesh_terms: D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D002412:Cations / Q000378:metabolism; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000378:metabolism; D016308:Enkephalin, Leucine-2-Alanine; D066298:In Vitro Techniques; D007700:Kinetics; D008566:Membranes / Q000378:metabolism; D008670:Metals / Q000378:metabolism; D051381:Rats; D011957:Receptors, Opioid / Q000378:metabolism*
chemical_list: D002412:Cations; D008670:Metals; D011957:Receptors, Opioid; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine
vernacular_title: O prirode kationsviazyvaiushchikh grupp tsentrov sviazyvaniia [[3H]Tyr1, D-Ala2, D-Leu5]énkefalina.