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  • Enkephalins (penta-peptides) have recently been discovered as regulators of nerve impulses involving pain in the brain. Apparently these peptides act as natural analgesics (pain-killers) and their action mimics that of morphine and other opiates. At present it is thought that the morphine-like effects are due to aromatic side chains on phenylanine and tyrosine which mimic a similar sturcture on morphine. Apparently, it does not make much difference whether the enkephalin contains methionine or leucine at the acid end of the peptide. The primary structures are:

    methionine-enkephaline: tyr - gly - gly - phe - met
    leucine-enkephalin: tyr - gly - gly - phe - leu


    QUES. Write the peptide structure for methionine-enkephalin. Enkephalin - Met - Chime in new window

    Quiz:Which amino acid is the N-terminal one?
    Which amino acid is the C-terminal one?

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