GO:0038046

Combining with an enkephalin, and transmitting the signal across the membrane by activating an associated G-protein. A enkephalin is a pentapeptide (Tyr-Gly-Gly-Phe-Met or Tyr-Gly-Gly-Phe-Leu) involved in regulating nociception in the body. [GOC:bf, Wikipedia:Enkephalin]