A critical comparison of three MS-based approaches for quantitative proteomics analysis

Area of Science:

• Proteomics
• Quantitative Mass Spectrometry

Background:

• Mass spectrometry (MS)-based proteomics is increasingly vital for biological discovery.
• Accurate and precise quantification of thousands of analytes in MS experiments remains a significant challenge.

Purpose of the Study:

• To assess the diagnostic accuracy of three popular data-dependent protein relative quantification methods: label-free (LF), dimethyl labeling (DML), and tandem mass tags (TMT).
• To evaluate the reproducibility and performance of these methods across multiple experimental runs and over time.

Main Methods:

• A mixed-species proteome (three species) with five replicates per condition was used.
• Data acquired on a quadrupole-Orbitrap mass spectrometer.
• Analysis performed using the MaxQuant/Perseus software suite; comparative analysis repeated three times over six months.

Main Results:

• Label-based methods (TMT, DML) reproducibly yielded a lower false positive rate compared to label-free.
• TMT and LF methods demonstrated similar and superior proteome coverage compared to DML, given the same instrument time.
• While proteome coverage and precision were consistent across replicates, sensitivity (correctly classifying true positives) showed lower reproducibility, particularly for subtle fold-changes (1.5).

Conclusions:

• TMT and LF offer advantages in proteome coverage over DML for quantitative proteomics.
• Reproducibility of sensitivity, especially for low fold-changes, is a critical concern in quantitative proteomics.
• Increased focus on data reproducibility is essential for advancing the field of quantitative proteomics.