Glutaminyl-peptide Cyclotransferase/QPCT in Human Brain. Glutaminyl-peptide Cyclotransferase/QPCT was detected in immersion fixed paraffin-embedded sections of human brain using Sheep Anti-Human Glutaminyl-peptide Cyclotransferase/QPCT Antigen Affinity-purified Polyclonal Antibody (Catalog # AF6368) at 3 µg/mL overnight at 4 °C. Before incubation with the primary antibody, tissue was subjected to heat-induced epitope retrieval using Antigen Retrieval Reagent-Basic (Catalog # CTS013). Tissue was stained using the Anti-Sheep HRP-DAB Cell & Tissue Staining Kit (brown; Catalog # CTS019) and counterstained with hematoxylin (blue). Specific staining was localized to neuronal cell bodies and processes. View our protocol for Chromogenic IHC Staining of Paraffin-embedded Tissue Sections.
Preparation and Storage
Sterile PBS to a final concentration of 0.2 mg/mL.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. *Small pack size (SP) is shipped with polar packs. Upon receipt, store it immediately at -20 to -70 °C
Stability & Storage
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.
Glutaminyl-peptide Cyclotransferase, also known as Glutaminyl Cyclase, catalyzes the conversion of N‑terminal L-glutaminyl residues of peptides to pyroglutamyl groups (1). The enzyme is present in the pituitary and adrenal glands, where it is important for the generation of the N‑terminal pyroglutamyl groups of peptide hormones such as neurotensin and thyrotropin-releasing hormone. Glutaminyl Cyclase also catalyzes the conversion of N‑terminal L‑glutamyl residues to pyroglutamyl residues (2). This activity may contribute to the formation of several amyloid-related plaque forming peptides, contributing to Alzheimer’s disease pathology. Glutaminyl Cyclase is also considered to be a diagnostic marker of thyroid tumors (3).
Busby, W.H. Jr. et al. (1987) J. Biol. Chem. 262:8532.
Schilling, S. et al. (2004) FEBS Lett. 563:191.
Griffith, O.L. et al. (2006) J. Clin. Oncol. 24:5043.
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