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.
Comprehensive Sialidase (Neuraminidase) Activity and Inhibition Profiling Services for Antiviral Drug Discovery and Vaccine Quality Control
Sialidase (neuraminidase; EC 3.2.1.18) is a glycoside hydrolase that catalyzes the cleavage of terminal sialic acid residues from various glycoconjugates, playing a critical role in the pathogenesis of influenza viruses, parainfluenza viruses, and certain bacterial infections. In the context of influenza, neuraminidase is a major surface antigen and the primary target of antiviral drugs such as oseltamivir and zanamivir. The accurate and sensitive detection of neuraminidase activity, combined with comprehensive inhibition profiling against drug candidates, is essential for antiviral drug discovery, monitoring drug resistance, and ensuring the potency and consistency of influenza vaccines. Our specialised analytical platform offers a fully validated suite of biochemical and biophysical assays for the precise characterisation of neuraminidase activity, kinetic parameters, and inhibition profiles, delivering high-quality, regulatory-ready data to support your research and development programs.
Understanding the Client's Need for Neuraminidase Detection and Analysis
Clients seeking neuraminidase detection services are typically driven by one or more of the following critical objectives. In antiviral drug discovery and development, the primary need is to quantify neuraminidase activity and to evaluate the inhibitory potency of novel compounds, enabling the identification of lead candidates with high efficacy and favourable selectivity profiles. In influenza surveillance and vaccine production, neuraminidase activity is a key measure of viral yield and vaccine potency, and its quantification is essential for lot release testing and for monitoring antigenic drift. In clinical research and diagnostics, measuring neuraminidase activity in patient samples can provide insights into disease severity and the emergence of drug-resistant viral strains. In quality control of biological reagents, verifying the activity of recombinant neuraminidase standards is essential for assay development and diagnostic kit production. In regulatory submissions, comprehensive data on enzyme activity, inhibitor selectivity, and stability are required for the approval of novel antiviral agents, vaccines, and diagnostic devices. Our service is architected to address these diverse needs with a flexible, ISO 17025‑accredited analytical framework that adapts to the specific viral subtype, sample matrix, and client's research or regulatory context.
Our Advanced Analytical Platform for Holistic Neuraminidase Characterisation
Our analytical platform is built upon a validated, multi-parameter approach to neuraminidase characterisation, integrating four interconnected modules: the Activity Quantification Module, the Kinetic and Inhibition Profiling Module, the Specificity and Substrate Profiling Module, and the Stability and Formulation Module.
The Activity Quantification Module employs a highly sensitive fluorometric assay using the widely accepted substrate 2′-(4-methylumbelliferyl)-α-D-N-acetylneuraminic acid (MUNANA), which is cleaved to release the fluorescent 4-methylumbelliferone (MU) product. We meticulously optimise assay conditions for each neuraminidase subtype (e.g., N1, N2, N3, and others) and sample matrix, ensuring maximal activity and specificity. We determine the specific activity (U/mg protein) with precision within ±2% RSD and a limit of detection (LOD) as low as 0.001 U/mL. The assay is performed in a 96-well or 384-well microplate format, enabling high-throughput screening of large compound libraries or multiple clinical samples.
The Kinetic and Inhibition Profiling Module provides detailed characterisation of enzyme-substrate interactions and inhibitor potency. For detailed kinetic characterisation, we calculate Michaelis-Menten parameters (Km, Vmax, kcat) and inhibition constants (IC50, Ki) for a panel of known inhibitors (e.g., oseltamivir carboxylate, zanamivir, peramivir) and test compounds, with 95% confidence intervals typically within ±5%. We perform full dose-response curves with at least 8 concentrations in triplicate, and we provide Dixon plots and Cornish-Bowden analyses to determine the mechanism of inhibition (competitive, uncompetitive, or mixed).
The Specificity and Substrate Profiling Module evaluates the enzyme's activity against a custom panel of sialylated substrates, including oligosaccharides and glycoproteins, to generate a specificity fingerprint that can distinguish between neuraminidase subtypes and reveal potential off-target effects. For clients working with complex biological matrices, such as viral culture supernatants or clinical specimens, we use UHPLC‑MS/MS to directly quantify the release of sialic acid products, providing mass accuracy < 2 ppm and enabling the detection of even trace levels of activity.
The Stability and Formulation Module assesses the enzyme's stability under various storage conditions (temperature, pH, freeze‑thaw) and its resistance to common interferents (e.g., serum proteins, detergents). Using Arrhenius modelling and deactivation kinetics, we predict shelf‑life and identify critical degradation pathways (e.g., deamidation, oxidation, aggregation).
Unmatched Analytical Sensitivity, Specificity, and Throughput
Our neuraminidase detection services are distinguished by their superior analytical performance and adaptability. The fluorogenic MUNANA assay provides a signal‑to‑noise ratio > 300:1 at the LOD, with linearity over four orders of magnitude and Z’‑factors consistently > 0.8, making our assays highly robust for high‑throughput screening. Our kinetic fitting software uses global non‑linear regression to provide precise estimates of Km and Vmax, with residual errors < 2%. For protein quantitation and subtype discrimination, we offer targeted proteomics (PRM) with stable isotope‑labelled peptide standards, achieving LOQs in the low fmol range and enabling the simultaneous quantitation of multiple neuraminidase subtypes in a single sample. Additionally, we offer isothermal titration calorimetry (ITC) to measure the binding thermodynamics of inhibitors, providing ΔH, ΔS, and binding stoichiometry with precision within ±2%.
Distinctive Advantages of Our Neuraminidase Detection Service
Our service provides several unique benefits that directly address client challenges. First, we have developed matrix‑specific sample preparation protocols for a wide variety of neuraminidase sources—including viral culture supernatants, recombinant proteins, and clinical specimens—that effectively preserve enzyme activity and protein integrity, achieving recoveries > 95% for all tested matrices. Second, we maintain a comprehensive reference library of neuraminidase subtypes and their known inhibitor profiles, enabling rapid method setup and confident benchmarking. Third, we offer a rapid screening service using a microplate‑based fluorogenic assay that provides semi‑quantitative activity data within 30 minutes of sample receipt—ideal for high‑throughput screening of compound libraries or clinical samples. Fourth, our customised kinetic and inhibition studies can be tailored to simulate physiological conditions, including the presence of serum proteins and relevant glycans. Fifth, we provide integrated data interpretation that links enzyme activity, inhibitor potency, and stability to biological or clinical outcomes (e.g., antiviral efficacy, vaccine potency, drug resistance), enabling clients to make informed decisions on candidate selection and application. Sixth, all our methods comply with ICH M10, FDA, and EMA guidelines on bioanalytical method validation, and we supply full validation dossiers (specificity, linearity, accuracy, precision, LOD, LOQ, robustness) along with detailed SOPs, ensuring that our data are readily accepted by regulatory authorities.
Broad Applications Across Antiviral Drug Discovery, Vaccine Quality Control, and Clinical Research
The versatility of our neuraminidase detection service spans a wide range of sectors. In antiviral drug discovery, our assays are critical for target validation, lead optimisation, and selectivity profiling of novel neuraminidase inhibitors. In influenza vaccine quality control, we quantify neuraminidase activity to ensure lot‑to‑lot consistency and potency, supporting regulatory submissions and market release. In clinical research and diagnostics, we measure neuraminidase activity in patient samples to monitor viral shedding, drug resistance, and disease progression. In academic research, our comprehensive profiling supports publication‑quality studies on enzyme mechanism, structure‑function relationships, and viral pathogenesis. In contract research organisations (CROs), our services provide robust data to support regulatory submissions. Our ability to tailor the analytical package to the specific virus subtype, sample type, and regulatory framework ensures that we serve a diverse global clientele with scientific rigour and practical relevance.
Commitment to Innovation, Quality, and Client Partnership
We are dedicated to advancing neuraminidase analytics through continuous technological improvement. Our current R&D includes the development of microfluidic‑based single‑enzyme activity assays for ultra‑sensitive detection, and the application of machine learning algorithms to predict inhibitor potency from chemical structure. We actively participate in inter‑laboratory proficiency testing for enzyme activity and protein analysis, and we contribute to the development of reference standards for neuraminidase. Our quality management system is ISO 9001 and ISO 17025 certified, and we follow GLP for all regulatory studies. We offer flexible engagement models—from single‑sample analysis to multi‑year collaborative projects—with dedicated project managers, volume discounts, and priority handling for time‑sensitive samples. Our global logistics provide specialised shipping kits (with stabilising buffers and temperature control) to preserve enzyme activity during transit. Turnaround times range from 1 business day for rapid screening to 10 business days for comprehensive kinetic, proteomic, and inhibition profiling. We maintain open communication, providing preliminary results upon request and final reports with expert commentary. Our success is measured by the confidence our clients have in their data and their ability to advance research, drug development, and public health. We invite you to partner with us to unlock the full potential of your neuraminidase research.
In summary, our neuraminidase detection service delivers a comprehensive, precise, and application‑oriented analytical solution that integrates activity quantification, kinetic and inhibition profiling, substrate specificity assessment, and stability evaluation. By combining advanced instrumentation with deep expertise in viral enzymology and translational science, we empower our clients to accelerate drug discovery, ensure vaccine quality, and improve clinical outcomes. We look forward to supporting your neuraminidase analysis needs with our state‑of‑the‑art analytical platform.