SRM-MRM Quantitative Proteomics Services
MtoZ Biolabs provides targeted quantitative proteomics services for predefined protein targets, supporting biomarker validation, candidate verification, and focused quantitative studies across biological samples.
High-resolution targeted LC-MS/MS workflows are tailored to target sequences, sample characteristics, and quantitative objectives, with relative and isotope-standard-assisted strategies available according to project needs.
- Targeted quantification of predefined protein and peptide targets
- High-resolution LC-MS/MS for focused validation studies
- Relative and isotope-standard-assisted quantitative strategies
What Is SRM-MRM Quantitative Proteomics?
SRM (Selected Reaction Monitoring) and MRM (Multiple Reaction Monitoring) are established targeted mass spectrometry strategies used to quantify predefined proteins or peptides. Unlike discovery proteomics, which surveys a broad range of proteins, targeted quantitative proteomics begins with a defined target list. Representative peptides are selected for proteins of interest and monitored through targeted LC-MS/MS analysis, allowing focused quantitative evaluation across samples.
This approach is particularly valuable after candidate proteins have already been identified and the next step is to verify their quantitative behavior across experimental groups, treatment conditions, or larger sample sets.
Li J. et al. Drug Discovery Today Technologies. 2021.
Figure 1. Schematic Diagram of SRM/MRM
Choose the Right Targeted Quantification Workflow
The appropriate quantitative strategy depends on the type of result required from the study.
|
Quantification Strategy |
Approach |
Best Suited For |
|
Relative Quantification |
Compares target peptide responses across samples or groups |
Candidate verification, group comparison, treatment-response studies |
|
Isotope-Standard-Assisted Quantification |
Incorporates stable isotope-labeled peptide standards |
Improved quantitative control and cross-sample comparison |
|
Concentration-Level Quantification |
Uses suitable standards together with calibration curves |
Projects requiring calculated peptide concentrations |
Relative quantification is appropriate when the main goal is to compare predefined targets between biological conditions. When stronger quantitative control or concentration-level results are required, stable isotope-labeled peptide standards and calibration strategies can be incorporated into the study design.
Target sequence, peptide behavior, sample matrix, target abundance, and sample scale are evaluated together before the final quantitative workflow is established.
Service at MtoZ Biolabs
MtoZ Biolabs supports SRM-MRM quantitative proteomics projects for predefined protein targets with available sequence information. Candidate targets may come from previous DDA or DIA studies, published research, known pathways, or established biological hypotheses.
Projects are developed around suitable signature peptides and analyzed using high-resolution targeted LC-MS/MS workflows. Orbitrap-based PRM acquisition is used for focused measurement of selected peptide targets, followed by quantitative analysis using established targeted proteomics data-processing workflows.
Study design can be configured for relative comparison or isotope-standard-assisted concentration measurement, depending on the analytical objective. For lower-abundance targets or challenging biological matrices, additional enrichment strategies can be evaluated as part of project planning.
Analysis Workflow
1. Target Review and Signature Peptide Selection
Protein identifiers and amino acid sequences are evaluated to identify representative peptides suitable for targeted measurement.
2. Sample Preparation and Digestion
Protein samples undergo reduction, alkylation, enzymatic digestion, and peptide cleanup prior to LC-MS/MS analysis.
3. High-Resolution Targeted LC-MS/MS
Prepared peptides are separated by nano-LC and analyzed using high-resolution targeted mass spectrometry acquisition.
4. Target Peptide Evaluation
Candidate peptides are evaluated based on sequence specificity, signal quality, and analytical performance.
5. Quantitative Analysis
Target peptide responses are processed for relative comparison or, when appropriate standards are included, concentration-level calculation.
Sample Submission Requirements
For protein solution samples:
- Total protein:>40 μg
- Protein concentration:>0.5 μg/μL
Original biological samples should be shipped on dry ice. Protein solutions should be prepared under LC-MS/MS-compatible conditions with minimal salt or detergent interference.
For project evaluation, please provide target protein IDs or sequences, sample type, sample number, and quantitative objectives. UniProt reference sequences or suitable customized databases can be incorporated according to project requirements.
Applications of SRM-MRM Quantitative Proteomics
1. Biomarker Candidate Validation
Evaluate predefined biomarker candidates across additional samples after discovery-stage screening.
2. Drug Response Research
Monitor selected proteins following treatment or biological perturbation to assess target-specific molecular responses.
3. Disease Mechanism Studies
Quantify known disease- or pathway-associated proteins to investigate focused molecular changes across biological conditions.
4. Cohort-Based Target Validation
Extend selected protein measurements across larger sample sets to confirm trends identified during earlier proteomics studies.
Why Choose MtoZ Biolabs?
1. Project-Specific Peptide Selection
Target sequences are evaluated individually to identify suitable signature peptides and appropriate digestion strategies for targeted analysis.
2. Flexible Quantification Design
Projects can be configured for relative comparison or isotope-standard-assisted concentration measurement according to research objectives.
3. Standardized Analytical Workflow
Standardized sample preparation and instrument maintenance support consistent targeted measurements across analytical batches.
4. Established Targeted Proteomics Analysis
Quantitative data are processed using targeted proteomics workflows such as Skyline, with UniProt or customized sequence databases incorporated where appropriate.
What Could be Included in the Report?
Depending on project design, the final data package may include:
1. Protein and Peptide Identification Results
2. Selected Signature Peptide Information
3. Relative or Concentration-Level Quantitative Results
4. Raw Mass Spectrometry Data
5. Processed Data and Basic PDF Report
FAQ
Q1: How are signature peptides selected for targeted protein quantification?
Signature peptides are evaluated based on sequence specificity, digestion compatibility, MS response, and analytical performance. The goal is to identify representative peptides that can provide reliable quantitative information for the predefined protein targets.
Q2: What if a target protein is present at low abundance?
Target abundance and sample matrix are considered during project design. When appropriate, enrichment approaches such as immunoprecipitation or other target-specific strategies may be evaluated to improve target detectability.
Q3: Can candidates identified by DIA or DDA be used for targeted quantification?
Yes. Candidate proteins generated from discovery proteomics are well suited for subsequent targeted quantitative validation once the target list has been established.
Q4: How long does a targeted quantitative proteomics project take?
A typical project requires approximately 3-6 weeks, depending on signature peptide selection, standard peptide preparation when required, calibration development, sample number, and instrument scheduling.
Contact Us
Contact MtoZ Biolabs with your target protein list, sample information, and quantitative objectives to discuss a targeted proteomics strategy tailored to your study.
MtoZ Biolabs, an integrated chromatography and mass spectrometry (MS) services provider.
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