Enkephalin is either of two pentapeptides (containing five amino acids) with OPIATE and ANALGESIC (painkilling) activity, occurring naturally in the brain, with a marked affinity for opiate receptors. ENDORPHIN was initially the name for all opioid-like NEUROTRANSMITTERS in the brain; the research team of Hans Kosterlitz and John Hughes gave their own name, enkephalin (a variant of en-cephal ["of the brain"]), to the two opioid pentapeptides that they had purified from ox brains (ca. 1977). They confirmed their discovery by showing that the effects of synthetic peptides were the same in bioassays using opiate RECEPTORS and that both Met⁵enkephalin and Leu⁵enkephalin were authentic endogenous opioid peptides.

See Also

Opiates/Opioids)

Bibliography

COOPER, J. R., BLOOM, F. E., & ROTH, R. H. (1996). The biochemical basis of neuropharmacology, 7th ed. New York: Oxford University Press.