M28 Zn-Peptidase Glutaminyl Cyclase (IPR037457)

Short name: M28_QC_like

Overlapping homologous superfamilies


Domain relationships

  • Peptidase M28 (IPR007484)
    • M28 Zn-Peptidase Glutaminyl Cyclase (IPR037457)


This entry represents a domain found in proteins belonging to the glutaminyl cyclase (QC) subfamily of the peptidase M28 family. QC is involved in N-terminal glutamine cyclization of many endocrine peptides and is typically abundant in brain tissue. N-terminal glutamine residue cyclization is an important post-translational event in the processing of numerous bioactive proteins, including neuropeptides, hormones, and cytokines during their maturation in the secretory pathway. The N-terminal pGlu protects them from exopeptidase degradation and/or enables them to have proper conformation for binding to the receptors [PMID: 16135565].

QCs are highly conserved from yeast to human [PMID: 18979624]. In humans, several genetic diseases, such as osteoporosis, appear to result from mutations of the QC gene. N-terminal glutamate cyclization into pyroglutamate (pGlu) is a reaction that may be related to the formation of several plaque-forming peptides, such as amyloid-(A) peptides and collagen-like Alzheimer amyloid plaque component, which play a pivotal role in Alzheimer's disease [PMID: 15063747].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0016603 glutaminyl-peptide cyclotransferase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.