Glutaminyl Peptide Cyclotransferase (QPCT)

QPCT encodes human pituitary glutaminyl cyclase, which is responsible for the presence of pyroglutamyl residues in many neuroendocrine peptides. The amino acid sequence of this enzyme is 86% identical to that of bovine glutaminyl cyclase.The deduced 361-amino acid protein has a calculated molecular mass of about 41 kD. It contains an N-terminal signal peptide region, several glycosylation and phosphorylation sites, and 2 cysteine residues conserved between the bovine and human enzymes. QPCT shares 86% overall sequence identity with the bovine homolog.Glutaminyl cyclase expression was upregulated in the cortices of individuals with Alzheimer disease and correlated with the appearance of pE-modified amyloid beta.