1PLW, 1PLX, 2LWC, 5E33, 5E3A
5179
18619
ENSG00000181195
ENSMUSG00000045573
P01210
P22005
NM_006211NM_001135690
NM_001002927NM_001348209
NP_001129162
NP_001002927NP_001335138
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, and to a lesser extent, leu-enkephalin.[5] 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.[5] 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,[6] amidorphin,[7] BAM-18,[8] BAM-20P,[9] BAM-22P,[9] peptide B,[10] peptide E,[11] and peptide F.[12]
Proenkephalin is produced by the medium spiny neurons of the striatum which undergo neurodegeneration in early stages of Huntington's disease (HD). PENK[13] and related peptides[14][15] measured in cerebrospinal fluid are proposed as potential biomarkers of disease progression in HD. Furthermore, PENK has been found associated with acute kidney injury[16] and glomerular filtration rate in steady-state and critically ill patients.[17][18]