The metabolic stability of the enkephalins

Richard J. Miller*, K. J. Chang, Pedro Cuatrecasas, Sam Wilkinson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


[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 languageEnglish (US)
Pages (from-to)1311-1317
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number4
StatePublished - Feb 21 1977

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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