title: [The effect of di- and trivalent metal ions on the binding of [3H-Tyr1, D-Ala2, D-Leu5] enkephalin to opiate receptors from the rat brain].
abstract: The influence of Ca2+, Mg2+, Mn2+, Sr2+, La3+, Nd3+, Sm3+, Eu3+, and Gd3+ ions on the binding of labeled, stable enkephalin analogue, [3H-Tyr1, D-Ala2, D-Leu5]enkephalin, to opiate receptors of the rat brain membrane preparations has been investigated. The formation of the complex can be described by a scheme involving at least two independent binding sites. The high affinity site does not discriminate the divalent and trivalent metal ions: all examined cations enhanced the enkephalin affinity for this site. The ligand binding to the low affinity site is potentiated only by Mn2+, Mg2+, and lathanoides. The maximal concentration of the binding sites of the above two types is not affected by the cations. The increase in the ionic strength of the solution entails a decrease in the affinity of the ligand for the high affinity binding site. It is shown that the effect of both di- and trivalent metal cations on the [3H-Tyr1, D-Ala2, D-Leu3] enkephalin binding is mediated through one cation attachment site on the respective enkephalin receptor.
mesh_terms: D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D002412:Cations; D055598:Chemical Phenomena; D002621:Chemistry; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000378:metabolism; D016308:Enkephalin, Leucine-2-Alanine; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000378:metabolism; D008670:Metals / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002412:Cations; D008670:Metals; D011957:Receptors, Opioid; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine
vernacular_title: Vliianie dvukh- i trekhvalentnykh ionov metallov na protsess kompleksoobrazovaniia [3H-Tyr1, D-Ala2, D-Leu5]énkefalina s opiatnymi retseptorami golovnogo mozga krysy.