Synthetic peptide SLTCLVKGFY competes with beta-endorphin for naloxone-insensitive binding sites on rat brain membranes.
The synthetic decapeptide Ser-Leu-Thr-Cys-Leu-Val-Lys-Gly-Phe-Tyr (termed immunorphin) corresponding to the sequence 364-373 of the CH3 domain of human immunoglobulin G heavy chain and its synthetic fragment VKGFY were found to compete with 125I-labeled beta-endorphin for high-affinity naloxone-insensitive binding sites on membranes isolated from the rat brain cortex (K(i)=1.18+/-0.09 and 1.58+/-0.11 nM, respectively). The binding specificity study revealed that these binding sites were insensitive not only to naloxone but to [Met(5)]enkephalin and [Leu(5)]enkephalin as well. The K(d) values characterizing the specific binding of 125I-labeled immunorphin and its fragment Val-Lys-Gly-Phe-Tyr to these binding sites were determined to be 2.93+/-0.27 nM and 3.17+/-0.29 nM, respectively.
Navolotskaya
Elena V
EV
Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 142290, Moscow Region, Pushchino, Russia. navolots@fibkh.serpukhov.su
Zargarova
Tatyana A
TA
Malkova
Natalia V
NV
Krasnova
Svetlana B
SB
Zav'yalov
Vladimir P
VP
Lipkin
Valery M
VM
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007127:Immunoglobulin Constant Regions; D007074:Immunoglobulin G / Q000737:chemistry; D007142:Immunoglobulin gamma-Chains; D007700:Kinetics; D008024:Ligands; D008969:Molecular Sequence Data; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology*; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D001615:beta-Endorphin / Q000737:chemistry / Q000494:pharmacology*
D007127:Immunoglobulin Constant Regions; D007074:Immunoglobulin G; D007142:Immunoglobulin gamma-Chains; D008024:Ligands; D009292:Narcotic Antagonists; D009842:Oligopeptides; D010446:Peptide Fragments; D010455:Peptides; C445661:immunorphin; D009270:Naloxone; D001615:beta-Endorphin