What is "proenkephalin"

n. (context biochemistry English) A gene that is a precursor for leuenkephalin and metenkephalin.

Proenkephalin (PENK), formerly known as proenkephalin A (since proenkephalin B was renamed prodynorphin), is an endogenous opioid polypeptide hormone which, via proteolyic cleavage, produces the enkephalin peptides [[Met-enkephalin|[Met]enkephalin]], and to a lesser extent, [[Leu-enkephalin|[Leu]enkephalin]]. Upon cleavage, each proenkephalin peptide results in the generation of four copies of [Met]enkephalin, two extended copies of [Met]enkephalin, and one copy of [Leu]enkephalin. Contrarily, [Leu]enkephalin] is predominantly synthesized from prodynorphin, which produces three copies of it per cleavage, and no copies of [Met]enkephalin. Other endogenous opioid peptides produced by proenkephalin include adrenorphin, amidorphin, BAM-18, BAM-20P, BAM-22P, peptide B, peptide E, and peptide F.