Collect. Czech. Chem. Commun. 1990, 55, 2328-2338

The interactions of opioids with enterocyte membranes: Evidence for enzyme-catalysed covalent binding

Konstantin N. Yarigin

Cardiology Research Center of the U.S.S.R. Academy of Medical Sciences, 121552 Moscow, U.S.S.R.


The binding of the synthetic opioid hexapeptide Tyr-D-Ala-Gly-Phe-Leu-Arg (dalargin) to rat enterocyte membranes has been studied and compared to its interaction with central opioid receptors. The binding was apparently low affinity, time- and temperature-dependent, sensitive to NaF and N-ethylmaleimide, and esentially irreversible even after incubation with trichloracetic acid. It was inhibited by ascorbate and substances containing hydroxybenzol moieties or halogenósubstituted aromatic rings. The binding of [14C]phenol and [3H]tyrosine to rat enterocyte membranes was very similar to the binding of dalargin. The interaction of dalargin with rat enterocyte membranes differed in many ways from its binding to opioid receptors, but it was similar to the covalent binding of hydroxybenzol derivatives to proteins catalyzed by cytochrome P-450 enzyme complex.