Pyroglutamyl-peptidase I

Pyroglutamyl-peptidase I (PPI), also known as 5-oxoprolyl-peptidase, is an enzyme that catalyzes the removal of pyroglutamic acid (also known as pyroglutamate or pGlu) from the N-terminus of peptides and proteins. This enzyme is part of the family of hydrolases, specifically those acting on carbon-nitrogen bonds other than peptide bonds, in linear amides. The systematic name of this enzyme class is N-terminal-pyroglutamyl-peptide hydrolase.

Function

Pyroglutamyl-peptidase I is involved in the metabolism of neuropeptides and hormones, many of which have an N-terminal pyroglutamyl residue. This residue is important for their stability and biological activity. By removing the pyroglutamyl group, PPI can regulate the activity of these molecules.

Structure

The structure of PPI is characterized by a catalytic triad consisting of cysteine, histidine, and aspartate residues. This is a common feature of many hydrolases. The enzyme is a homohexamer, with each subunit containing approximately 200 amino acid residues.

Clinical significance

Alterations in the activity of PPI have been associated with various neurological disorders, including schizophrenia, Alzheimer's disease, and mental retardation. In addition, PPI inhibitors have potential therapeutic applications in the treatment of these disorders.

See also

• Pyroglutamate
• Peptidase
• Neuropeptide
• Hormone

References

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