QPCT Human
Description
QPCT produced in Sf9 Baculovirus cells is a single, glycosylated polypeptide chain containing 339 amino acids (29-361a.a.) and having a molecular mass of 38.7kDa (Molecular size on SDS-PAGE will appear at approximately 28-40kDa). QPCT is expressed with a 6 amino acid His tag at C-Terminus and purified by proprietary chromatographic techniques.
Product Specs
Product Science Overview
Glutaminyl-Peptide Cyclotransferase (QPCT) is an enzyme that plays a crucial role in the post-translational modification of proteins. It catalyzes the conversion of N-terminal glutaminyl residues into pyroglutamyl residues, a modification that is essential for the stability and function of various peptide hormones and neuropeptides. This enzyme is particularly significant in the pituitary and adrenal glands, where it is involved in the generation of N-terminal pyroglutamyl groups of peptide hormones such as neurotensin and thyrotropin-releasing hormone .
Recombinant human QPCT is a form of the enzyme that is produced using recombinant DNA technology. This involves inserting the gene that encodes QPCT into a suitable host cell, such as the insect cell line Spodoptera frugiperda (Sf21), which is then cultured to produce the enzyme. The recombinant enzyme is typically tagged with a histidine tag to facilitate purification and is supplied in a carrier-free form to avoid interference from other proteins .
The preparation of recombinant human QPCT involves several steps:
- Gene Cloning: The gene encoding human QPCT is cloned into an expression vector.
- Transformation: The expression vector is introduced into the host cells (e.g., Sf21 cells).
- Expression: The host cells are cultured under conditions that promote the expression of the QPCT enzyme.
- Purification: The enzyme is purified using affinity chromatography, taking advantage of the histidine tag. The purity of the enzyme is typically greater than 95%, as determined by SDS-PAGE and silver staining .
The activity of recombinant human QPCT is measured by its ability to convert glutaminyl-AMC (a synthetic substrate) to pyroglutamyl-AMC. The specific activity of the enzyme is greater than 550 pmol/min/μg under the described conditions . This enzymatic activity is crucial for the formation of stable and functional peptide hormones and neuropeptides.
Recombinant human QPCT is used in various research applications, including:
- Studying Post-Translational Modifications: Understanding the role of pyroglutamylation in protein stability and function.
- Drug Development: Investigating the enzyme’s role in diseases and developing inhibitors as potential therapeutic agents.
- Biochemical Assays: Serving as a standard in enzyme activity assays and other biochemical studies .
