Pyroglutamyl Peptidase I (PGPEP1)

Pyroglutamyl peptidase I (EC 3.4.19.3) catalyzes the hydrolysis of N-terminal pyroglutamyl residues from oligopeptides and proteins.The human and mouse sequence encode deduced proteins of 209 amino acids that share 95% sequence identity with each other and approximately 30% identity with bacterial forms of the enzyme. Like other members of the C15 family of cysteine peptidases, PGPEP1 contains the conserved catalytic residues of glutamate, cysteine, and histidine. It has no N-terminal hydrophobic sequence, consistent with a cytosolic localization. Gel filtration chromatography determined that the active molecular mass of PGPEP1 was similar to its approximately 24-kD calculated molecular mass, indicating that it acts a monomer.