[Met5] and [Leu5]-enkephalins inhibit 3H-naloxone binding to brain opiate receptors much more effectively at 4°C than at 25°C. At 25°C several protease inhibitors potentiate the action of the enkephalins. Bacitracin is the most effective of these. In the presence of 100 μg/ml of bacitracin, the potencies of [Met5]- and [Leu5]-enkephalins are similar to those at 4°C. Some protease inhibitors, such as TLCK and TAME, are effective by themselves in inhibiting the binding of 3H-naloxone. Enkephalins with D-amino acids in the 2-position are equally effective at 0°C and at 25°C and their action is not potentiated by bacitracin. In particular, [D-Ala2]-enkephalins do not seem to be significantly degraded by the membrane enzymes which destroy the natural enkephalins.
|Original language||English (US)|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Feb 21 1977|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology