Met-enkephalin

Met-enkephalin, sometimes referred to as opioid growth factor (OGF) is an endogenous opioid peptide neurotransmitter found naturally in many parts of the animal and human's body. One of the primary locations is in segment II of the dorsal horn of the spinal cord. Also present in the CNS (central nervous system), it is one of the two forms of enkephalin; the other is leu-enkephalin. The tyrosine residue at position 1 is thought to be analogous to the 3-hydroxyl group on morphine.