Antibody Deamidation and Isomerization Analysis Service

Deamidation and isomerization are among the most common chemical modifications in antibodies. Deamidation refers to the chemical reaction of the side chain of asparagine (Asn) residues, converting them into aspartic acid (Asp) or isoaspartic acid (isoAsp). Isomerization usually occurs in aspartic acid residues (Asp), where a five-membered succinimide intermediate forms and generates isoAsp. Both modifications can alter the charge state and local conformation of antibodies, which may affect protein stability, binding activity, and in vivo metabolism.

 

Hoffmann, D. et al. MAbs. 2024.

Figure 1. Mechanism of Asparagine Deamidation and Aspartate Isomerization

 

As a result, antibody deamidation and isomerization analysis has become an essential step in antibody development and quality control. It helps to identify potential structural heterogeneity and provides critical data for evaluating pharmacodynamic consistency and long-term stability. Leveraging advanced mass spectrometry and chromatography platforms, together with extensive expertise in proteomics, MtoZ Biolabs offers systematic and reliable antibody deamidation and isomerization analysis service to support both research and biopharmaceutical development.

 

Services at MtoZ Biolabs

MtoZ Biolabs’ antibody deamidation and isomerization analysis service integrates multidimensional separation with high-resolution detection, combined with comprehensive data analysis, to ensure accurate localization and quantification of different modifications.

1. LC-MS/MS Peptide Mapping

• Antibodies are enzymatically digested into peptides and analyzed by LC-MS/MS.
• Deamidation typically results in a peptide mass increase of +0.984 Da, while isoAsp produces characteristic fragment ions in MS/MS spectra.
• This approach enables site-specific identification and relative quantification.

 

2. High-Resolution Mass Spectrometry

• High-resolution platforms such as Orbitrap or Q-TOF are applied to distinguish isomers and subtle mass differences.
• Fragmentation methods such as ETD/ECD can be combined to enhance isoAsp identification specificity.

 

3. Chromatographic Separation

• Reversed-Phase HPLC (RP-HPLC): Separates deamidated from unmodified peptides based on polarity differences.
• Ion Exchange Chromatography (IEX): Differentiates deamidated products by charge state.
• Capillary Electrophoresis (CE): Profiles charge variants of intact antibodies, providing an overall view of modification levels.

 

By combining these complementary techniques, MtoZ Biolabs delivers a complete solution from peptide-level site analysis to overall charge variant characterization.

 

Analysis Workflow

1. Sample preparation and digestion: Pretreat and enzymatically digest antibodies to obtain analyzable peptides.

2. Chromatographic separation and MS detection: Apply HPLC or CE for peptide or intact antibody separation, followed by high-resolution MS acquisition.

3. Data interpretation: Confirm deamidation and isomerization sites using databases and diagnostic fragment ions.

4. Quantification and reporting: Calculate modification ratios and provide detailed spectra with annotated results.

 

Service Advantages

1. Integrated Analytical Approaches

Rather than relying on a single method, MtoZ Biolabs combines LC-MS/MS, HPLC, IEX, and CE. This enables precise identification of modification sites and comprehensive profiling of antibody charge variants, ensuring reliable and well-rounded results.

 

2. High Sensitivity and Resolution

Our antibody deamidation and isomerization analysis service leverages Orbitrap and Q-TOF systems that deliver high mass accuracy and sensitivity, enabling detection of low-abundance modifications and subtle mass differences. Multiple fragmentation modes (CID, HCD, ETD) further enhance the discrimination of Asp versus isoAsp.

 

3. Extensive Antibody Expertise

With deep experience in antibody characterization, MtoZ Biolabs understands subclass-specific differences and challenges in deamidation and isomerization, allowing us to tailor analytical strategies to each project.

 

4. Transparent Pricing

We follow a one-time charge model with clear and transparent pricing, free from hidden costs or additional fees.

 

Applications

✔️ Antibody drug development: Evaluate the structural stability of candidate molecules and select optimal engineering strategies.

✔️ Quality control and consistency: Verify modification consistency across production batches to meet regulatory standards.

✔️ Stability studies: Monitor modification trends under different storage conditions to guide formulation optimization.

✔️ Mechanistic studies: Assess how residue modifications impact antibody binding affinity and biological function.

 

FAQs

Q1: Are deamidation and isomerization common in antibodies?

A1: Yes. Asn residues are highly reactive, especially in Gly-Asn sequences, and are prone to deamidation. Asp residues may also undergo isomerization. These are among the most frequent chemical modifications observed in antibodies.

 

Q2: Can Asp and isoAsp be distinguished?

A2: Yes. High-resolution MS/MS combined with characteristic fragment ions allows clear distinction between Asp and isoAsp and enables relative quantification.

 

Sample Submission Suggestions

1. Provide ≥100 µg of purified antibody at ~1 mg/mL concentration.

2. Samples should be in buffer, without high salt or high concentrations of surfactants.

3. For special testing requirements, please contact us for detailed submission guidelines.

 

Deliverables

1. Full experimental methods and workflow records

2. Antibody peptide mapping results and MS/MS spectra

3. Deamidation and isomerization site information with quantitative data

4. Charge variant analysis report for intact antibodies

5. Data interpretation and summarized conclusions

 

Antibody deamidation and isomerization are key indicators of structural stability and are critical in both drug development and regulatory evaluation. With advanced MS platforms and a skilled scientific team, MtoZ Biolabs provides systematic and reliable Antibody Deamidation and Isomerization Analysis Service that ensures comprehensive characterization and accurate assessment of antibody modifications. Whether for academic research or therapeutic development, we deliver robust data to support your project.

 

Contact MtoZ Biolabs today to begin your antibody deamidation and isomerization analysis.