Purity: > 90% by SDS - PAGE Format: Liquid. In Phosphate Buffered Saline (pH 7.4) containing 10% glycerol.. QPCT, also known as glutaminyl-peptide cyclotransferase, is responsible for the biosynthesis of pyroglutamyl peptides. This protein has a bias against acidic and tryptophan residues adjacent to the N-terminal glutaminyl residue and a lack of importance of chain length after the second residue. It catalyzes N-terminal pyroglutamate formation. In vitro, it catalyzes pyroglutamate formation of N-terminally truncated form of APP amyloid-beta peptides [Glu-3]-beta-amyloid. Recombinant human QPCT, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.