QPCT Antibody: Applications, Specificity & Research Use

QPCT Antibody is a specialized immunological reagent designed to detect and study glutaminyl-peptide cyclotransferase (QPCT), an enzyme critically involved in pyroglutamate formation at the N-terminus of secreted peptides and proteins.

Product Name

QPCT Antibody

Catalog Number

Ab349235

Target Protein

Glutaminyl-peptide cyclotransferase (QPCT)

Target Function

Catalyzes the conversion of N-terminal glutamine residues to pyroglutamate in secreted peptides and proteins

Research Relevance

Implicated in neurodegeneration, Alzheimer's disease, and inflammatory processes via pyroglutamate-modified amyloid-beta and other substrates

Supplier

Aladdin Scientific

Target Biology: What Is QPCT?

Glutaminyl-peptide cyclotransferase (QPCT), also known as glutaminyl cyclase (QC), is an enzyme that catalyzes the post-translational cyclization of N-terminal glutamine (and, under certain conditions, glutamate) residues into pyroglutamate. This modification is found on a wide range of bioactive peptides and proteins, including thyrotropin-releasing hormone (TRH), gonadotropin-releasing hormone (GnRH), and amyloid-beta (Aβ) peptides.

Pyroglutamate modification at the N-terminus confers increased resistance to aminopeptidase degradation, thereby enhancing the stability and bioactivity of the modified peptide. QPCT is expressed in various tissues, with notable expression in the brain, liver, and secretory organs, positioning it as an enzyme of broad physiological and pathological relevance.

In the context of neurodegeneration, N-terminally truncated and pyroglutamate-modified Aβ species (Aβ3(pE)-42) generated by QPCT activity are considered particularly aggregation-prone and neurotoxic, making QPCT a target of active investigation in Alzheimer's disease research.

Antibody Overview and Intended Applications

The QPCT Antibody (catalog number Ab349235) from Aladdin Scientific is intended for use in research applications targeting the QPCT protein. Antibodies against QPCT are commonly employed in techniques such as Western blotting (WB), immunohistochemistry (IHC), immunofluorescence (IF), and enzyme-linked immunosorbent assay (ELISA), enabling researchers to assess QPCT expression levels, tissue localization, and protein interactions.

When selecting an antibody for a specific application, researchers should confirm validated applications, species reactivity, and recommended dilution ranges in the full product datasheet. Please consult the Aladdin Scientific product page for Ab349235 for the most current and validated application data.

QPCT antibodies are valuable tools in studies focused on: amyloid precursor protein processing, neuroinflammation signaling, hormonal peptide maturation, and the validation of QPCT inhibitor efficacy in preclinical models.

Recommended Protocol for Western Blotting with QPCT Antibody

The following is a general guideline for Western blot detection of QPCT. Always verify specific conditions against the Ab349235 product datasheet before proceeding.

1. Sample preparation: Lyse cells or homogenize tissue in RIPA buffer supplemented with protease inhibitors. Determine total protein concentration by BCA or Bradford assay.
2. Gel electrophoresis: Load 20–40 µg total protein per lane on an SDS-PAGE gel (10–12% polyacrylamide recommended for QPCT, expected molecular weight approximately 40 kDa). Run at 100–120 V until adequate separation is achieved.
3. Transfer: Transfer proteins to a PVDF or nitrocellulose membrane using wet or semi-dry transfer conditions.
4. Blocking: Block membrane for 1 hour at room temperature in 5% non-fat dry milk or 5% BSA in TBST.
5. Primary antibody incubation: Incubate with QPCT Antibody (Ab349235) at the manufacturer-recommended dilution overnight at 4°C.
6. Secondary antibody and detection: Wash 3× with TBST, incubate with appropriate HRP-conjugated secondary antibody for 1 hour at room temperature, wash again, and detect with ECL substrate.

Note: Exact dilutions, blocking conditions, and expected band sizes should be confirmed in the current Ab349235 product datasheet. Flag this section for review if datasheet parameters differ.

Storage, Handling, and Quality Considerations

Proper storage and handling of QPCT Antibody (Ab349235) are essential to maintain reagent integrity and ensure reproducible results across experiments. General best practices for antibody storage include:

• Temperature: Store antibodies at –20°C for long-term storage. Avoid repeated freeze-thaw cycles, which can degrade antibody performance. Aliquot upon receipt if repeated access is anticipated.
• Buffer conditions: Most antibodies are supplied in PBS or Tris-based buffer containing a stabilizer such as glycerol or BSA with a preservative such as sodium azide. Refer to the Ab349235 datasheet for the exact formulation.
• Concentration and volume: Note the supplied concentration and total volume to calculate the number of experiments possible at the recommended dilution.
• Lot-to-lot consistency: When transitioning between antibody lots, run a parallel comparison to ensure consistency in signal intensity and specificity.

If you experience unexpected results such as no signal, high background, or non-specific bands, consult the troubleshooting section of the Aladdin Scientific technical support resources or contact our scientific support team directly.

Frequently asked questions

What is QPCT and why is it an important research target?

QPCT (glutaminyl-peptide cyclotransferase) is an enzyme that converts N-terminal glutamine residues into pyroglutamate on secreted peptides and proteins. It is important because its activity influences the stability and bioactivity of hormonal peptides and because QPCT-generated pyroglutamate-modified amyloid-beta species are implicated in Alzheimer's disease pathology, making QPCT a target for both basic and translational research.

Which applications is the QPCT Antibody (Ab349235) validated for?

Antibodies targeting QPCT are commonly used in Western blotting, immunohistochemistry, immunofluorescence, and ELISA. For the specific validated applications and recommended conditions for Ab349235, please refer to the current product datasheet available on the Aladdin Scientific website, as validated applications may vary by lot.

How should I store QPCT Antibody to maintain its activity?

Store QPCT Antibody at –20°C for long-term use and avoid repeated freeze-thaw cycles by aliquoting the antibody upon receipt. Keep on ice during experimental use. Always refer to the specific storage conditions stated on the Ab349235 product datasheet, as formulation details may influence optimal storage requirements.

What positive control samples can I use when testing QPCT Antibody?

Cell lines or tissues known to express QPCT endogenously—such as brain tissue or certain neuronal cell lines—are commonly used as positive controls. Recombinant QPCT protein can also serve as a positive control for Western blotting. Verify endogenous expression levels in your specific model system using published expression databases before proceeding.

References

1. Schilling S, Zeitschel U, Hoffmann T, et al. Glutaminyl cyclase inhibition attenuates pyroglutamate Abeta and Alzheimer's disease-like pathology. Nature Medicine, 2008.
2. Cynis H, Schilling S, Bäthge-Anhalt M, et al. Isolation of an isoenzyme of human glutaminyl cyclase: retention in the Golgi complex suggests a role in the protein maturation machinery. Journal of Molecular Biology, 2008.
3. Busby WH Jr, Quackenbush GE, Humm J, Youngblood WW, Kizer JS. An enzyme(s) that converts glutaminyl-peptides into pyroglutamyl-peptides. Presence in pituitary, brain, adrenal medulla, and lymphocytes. Journal of Biological Chemistry, 1987.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.