Protein Glycosylation Analysis Using the Agilent Cary 630 FTIR Spectrometer

Importance of the Topic

Protein glycosylation is a critical quality attribute affecting stability, efficacy and safety of therapeutic proteins. Reliable analytical methods are essential to monitor glycosylation profiles across development and manufacturing workflows.

Goals and Study Overview

This study demonstrates a fast, nondestructive FTIR spectroscopy approach using an Agilent Cary 630 to identify and compare glycosylation levels in various monoclonal antibodies and glycoproteins.

Methodology and Instrumentation

• Instrument: Agilent Cary 630 FTIR with diamond ATR module
• Software: Agilent MicroLab Expert
• Spectral settings: 4000–650 cm–1 range, 2 cm–1 resolution, 140 sample scans, 128 background scans
• Sample preparation: mAbs desalted via spin columns, protein solutions at 5 mg/mL, 15 µL loaded on ATR and cleaned between measurements
• Optional deglycosylation: PNGase F treatment at 37 °C overnight in Tris buffer pH 8.0
• Data processing steps: background subtraction, baseline correction, normalization (1718–1476 cm–1), Savitzky–Golay smoothing, peak integration (1179–965 cm–1)

Main Results and Discussion

• Distinct amide I (1600–1800 cm–1) and amide II (1470–1570 cm–1) bands observed for protein secondary structure
• Glycan region (1200–950 cm–1) shows unique carbohydrate absorption correlated to glycosylation levels
• Buffer components interfere in the glycan region; desalting via spin columns is essential
• Spectrum integration in 1179–965 cm–1 correlates with glycan content across seven proteins, matching expected glycosylation trends
• Comparative FTIR analysis of innovator versus biosimilar mAbs and deglycosylated samples confirms method sensitivity to glycan removal

Benefits and Practical Applications of the Method

• Rapid, label-free analysis of intact glycoproteins
• Minimal sample preparation and short measurement times (<1 minute per sample)
• Non-destructive technique compatible with routine quality control
• Software-driven workflow simplifies data processing and reduces time to result
• Suitable for batch consistency checks and comparability studies

Future Trends and Opportunities

• Integration with process analytical technology (PAT) for real-time monitoring
• Combining FTIR with complementary techniques (e.g. mass spectrometry, chromatography) for detailed glycoform profiling
• Development of advanced chemometric and machine learning models for automated spectrum interpretation
• Exploration of portable FTIR platforms for at-line GMP environments

Conclusion

FTIR spectroscopy on the Agilent Cary 630 provides a straightforward, efficient approach to assess global glycosylation in therapeutic proteins. Its nondestructive nature, minimal sample preparation and rapid analysis make it a valuable addition to quality control and comparability workflows during biopharmaceutical development and manufacturing.

References

1. He M; Zhou X; Wang X. Glycosylation: Mechanisms Biological Functions and Clinical Implications. Signal Transduction Targeted Ther. 2024 9(1):194
2. Derenne A; Derfoufi KM; Cowper B; Delporte C; Goormaghtigh E. FTIR Spectroscopy as an Analytical Tool to Compare Glycosylation in Therapeutic Monoclonal Antibodies. Anal Chim Acta. 2020 1112:62–71
3. Khajehpour M; Dashnau JL; Vanderkooi JM. Infrared Spectroscopy Used to Evaluate Glycosylation of Proteins. Anal Biochem. 2006 348(1):40–48
4. Derenne A; Derfoufi KM; Cowper B; Delport C; Butré CI; Goormaghtigh E. Analysis of Glycoproteins by ATR-FTIR Spectroscopy: Comparative Assessment. Methods Mol Biol. 2021 2271:361–374
5. Yang Y; Wang G; Song T; Lebrilla CB; Heck AJR. Resolving the Micro-Heterogeneity and Structural Integrity of Monoclonal Antibodies by Hybrid Mass Spectrometric Approaches. mAbs. 2017 9(4):638–645