DDA in Proteomics: Data-Dependent Acquisition Explained

Data-dependent acquisition (DDA) triggers MS2 on precursors chosen from each MS1 survey, typically Top N by intensity, making it a core strategy for peptide identification and DIA spectral library generation.

Key Takeaways

• MS1 survey → Top N selection → isolated MS2 → database search.
• DDA spectra are clean and work with established search engines.
• Abundance bias and stochastic sampling limit cohort reproducibility.
• DDA and DIA are complementary: libraries from DDA scale with DIA.

Related Services

Protein Identification by LC-MS/MS Service

Protein Identification Service by Shotgun Proteomics

Qualitative Proteomics Analysis Service

4D-DIA Quantitative Proteomics Service

FAQ

1. What is Top N?

The N most intense precursors selected for MS2 after each MS1 scan.

2. Is DDA still used?

Yes. For discovery, libraries, and high-confidence MS/MS-driven identification.

3. How does DDA support DIA?

DDA experiments often build or extend spectral libraries used in DIA searches.

Conclusion

DDA is not replaced by DIA; the two modes address different stages of discovery and quantification workflows.