Proenkephalin

Proenkephalin is a protein that in humans is encoded by the PENK gene. The protein encoded by this gene is a preproprotein that is cleaved to form multiple protein products. These products include the opioid peptides enkephalin and dynorphin, which are packaged into dense core vesicles in the cell body and axon terminals. Opioid peptides have a variety of physiological roles, including roles in pain perception and responses to stress. PENK mutations have been associated with various human diseases, including Parkinson's disease and alcohol addiction.

Structure

The PENK gene is located on the short (p) arm of chromosome 8 at position 21.3, from base pair 18,977,763 to base pair 18,984,423. The gene is composed of 4 exons and spans approximately 6.7 kb. The PENK preproprotein is 267 amino acids in length and is cleaved to form the mature peptides.

Function

The protein encoded by the PENK gene is a preproprotein that is cleaved to form multiple protein products. These products include the opioid peptides enkephalin and dynorphin, which are packaged into dense core vesicles in the cell body and axon terminals. Opioid peptides have a variety of physiological roles, including roles in pain perception and responses to stress.

Clinical significance

PENK mutations have been associated with various human diseases, including Parkinson's disease and alcohol addiction. In Parkinson's disease, decreased PENK expression has been observed in the substantia nigra. In alcohol addiction, PENK expression is increased in the nucleus accumbens.

See also

• Enkephalin
• Dynorphin
• Opioid peptide
• Parkinson's disease
• Alcohol addiction