Reasons for choosing our testing services
ZHONGXI Testing has obtained inspection qualification certifications from multiple countries and regions worldwide. We possess a senior testing team and advanced testing methods, providing independent, impartial, and professional third-party verification services for global carbon projects.
Internationally recognized authority
Certified by multiple international standards such as CNAS, VCS, and GS, with reports universally applicable worldwide.
Global service capability
Covering 140+ countries and regions, it supports on-site detection and remote verification in multiple languages.
Professional experimental methods
Adopt standard experimental methods to ensure accurate and reliable data.
Professional Prolyl Endopeptidase (PEP) Activity & Inhibition Testing Service
You are searching for prolyl endopeptidase detection because you need to perform this assay—whether to screen enzyme inhibitors, measure endogenous PEP activity in biological samples, or validate recombinant enzyme purity. We offer a complete detection service that delivers quantitative, sensitive, and specific measurement of prolyl endopeptidase (EC 3.4.21.26) across multiple sample types.
What We Detect – Beyond Simple Activity Readouts
Our prolyl endopeptidase detection goes far from basic fluorescent endpoint assays. We measure genuine endoproteolytic activity against native or synthetic substrates using ultra‑sensitive FRET‑peptides (Z‑GP‑AMC, Suc‑GP‑AMC, and internally quenched substrates). We also perform kinetic characterisation (kcat, Km, Vmax) at sub‑nanomolar enzyme concentrations. For complex matrices, we combine immunocapture with activity detection (iPEP assay) to resolve true PEP signal from interfering proteases. Additionally, we offer inhibition profiling against 50+ standard inhibitors (Z‑prolyl‑prolinal, KYP‑2047, S17092, etc.) with IC50 and inhibition mechanism (competitive/uncompetitive/mixed) determination.
How Deep We Go – From Endpoint to High‑Throughput & Mass Spectrometry
We don't just report activity units. Our advanced pipeline includes LC‑MS/MS based product identification (detecting specific cleavage after proline residues), capillary electrophoresis‑based separation of substrate/product for label‑free quantitation, and high‑throughput 1536‑well plate format screening for compound libraries (up to 100,000 tests per week). For challenging samples (tissue homogenates, plasma, fermentation broths), we deploy sample clean‑up via immunoaffinity or size‑exclusion spin columns to eliminate false positives. Our microfluidic enzymatic activity chip can measure PEP from as few as 500 cells or 1 µL of mouse brain lysate.
Why Our Prolyl Endopeptidase Detection Stands Out – Precision, Specificity & Flexibility
1. Substrate versatility: We offer a library of 15 different prolyl‑endopeptidase substrates (including Z‑GP‑AMC, Z‑AP‑MCA, and internally quenched Abz‑GP‑Dap(Dnp)‑OH) to match your exact isoform or species (human, rat, bacterial, Flavobacterium).
2. Interference‑proof chemistry: Our assays include selective PEP inhibitors as built‑in specificity controls and orthogonal detection by LC‑MS to confirm that activity is truly due to prolyl endopeptidase.
3. Deep kinetic analysis: We provide full progress curves under substrate inhibition conditions, pH optima profiling (pH 4.0–9.0), and temperature stability (4°C to 45°C) – essential for drug discovery and enzyme engineering.
4. Regulatory readiness: Our PEP detection protocols are GCLP‑compliant and have supported three IND filings for PEP inhibitors targeting cognitive disorders and celiac disease.
5. Expert interpretation: You receive a detailed report with specific activity (µmol/min/mg), inhibitor IC50 curves, Hill coefficients, and residual activity heatmaps – plus recommendations for follow‑up orthogonal validation.
Who Relies on Our PEP Detection – Real‑World Impact
Pharmaceutical companies use our service to screen 10,000+ compounds per project for selective PEP inhibition, eliminating off‑target cathepsin or dipeptidyl peptidase activity. Academic neuroscience groups send us post‑mortem brain tissue to measure PEP dysregulation in Alzheimer’s and Parkinson’s models – we routinely detect changes as low as 15% difference with coefficient of variation <8%. One enzyme manufacturer validated their recombinant PEP purity (99.7% by active site titration) using our orthogonal FRET/MS platform, which identified a previously hidden autolysis fragment.
Ready to Run Your Prolyl Endopeptidase Detection?
Send us purified enzyme (≥1 µg), tissue lysates (≥50 µL), cell extracts, or plasma/serum. We will perform activity measurement, inhibitor testing, kinetic characterisation, or inhibition screening – all with full positive/negative controls and detailed documentation. Request a free feasibility consultation; we will propose the optimal detection strategy within 48 hours.