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Updated: Sep 21, 2025
Evaluation of Protein–Protein Interactions using an On-Membrane Digestion Technique
Published on: July 19, 2019
Investigation of Tryptic Protein Digestion in Microdroplets and in Bulk Solution
Yongling Ai1, Jeffrey Xu1, Harsha P Gunawardena2
1Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States.
Abstract:
Recent studies have shown that ultrafast enzymatic digestion of proteins can be achieved in microdroplet within 250 μs. Further investigation of peptides resulting from microdroplet digestion (MD) would be necessary to evaluate it as an alternative to the conventional bulk digestion for bottom-up and biotherapeutic protein characterization. Herein we examined and compared protein tryptic digestion in both MD and bulk solution. In the case of MD of β-lactoglobulin B, the preservation of long peptides was observed due to the short digestion time. In addition, MD is applicable to digest both high- and low-abundance proteins in mixture. In the case of digesting NIST 8671 mAb antibody containing a low level of commonly encountered host cell protein (HCP) PLBL2 (mAb:PLBL2 = 100:1 by weight), MD produced lower levels of digestion-induced chemical modifications of asparagine/glutamine deamidation, compared with overnight digestion. No significant difference between MD and bulk digestion was observed in terms of trypsin digestion specificity based on examination of semi- and unspecific-cleaved peptides. Our study suggests that MD, a fast digestion approach, could be adopted for bottom-up proteomics research and for peptide mapping of mAbs to characterize site-specific deamidation and glycosylation, for the purpose of development of biopharmaceuticals.
Insights
Microdroplet digestion (MD) offers a rapid alternative to conventional protein analysis. This ultrafast method preserves long peptides and reduces chemical modifications, proving effective for biopharmaceutical characterization.
Area of Science:
- Proteomics
- Biochemistry
- Analytical Chemistry
Background:
- Ultrafast enzymatic digestion of proteins in microdroplets (MD) has emerged as a novel technique.
- Further evaluation is needed to compare MD with conventional bulk digestion for protein characterization.
Purpose of the Study:
- To compare protein tryptic digestion efficiency and outcomes between microdroplet digestion (MD) and conventional bulk digestion.
- To assess the suitability of MD for bottom-up proteomics and biotherapeutic protein characterization.
Main Methods:
- Comparative analysis of protein tryptic digestion using MD and bulk solution methods.
- Examination of peptide preservation, digestion specificity, and chemical modifications (deamidation) in both methods.
- Analysis of high- and low-abundance proteins and a monoclonal antibody (mAb) mixture.
Main Results:
- MD preserved longer peptides due to shorter digestion times (250 μs).
- MD effectively digested both high- and low-abundance proteins in a mixture.
- MD resulted in lower deamidation of asparagine/glutamine in mAb digestion compared to overnight bulk digestion.
- No significant differences in trypsin digestion specificity were observed between MD and bulk digestion.
Conclusions:
- Microdroplet digestion (MD) is a viable, fast alternative to conventional bulk digestion for proteomics.
- MD is suitable for bottom-up proteomics and peptide mapping of mAbs, aiding in the characterization of deamidation and glycosylation for biopharmaceutical development.
