SILAC Proteomics Service

Overview

Stable Isotope Labeling by Amino acids in Cell culture (SILAC) is a metabolic labeling-based quantitative proteomics strategy that enables comparison of protein abundance between different cellular conditions.

During SILAC experiments, cells are cultured with amino acids containing different isotope compositions, generating distinguishable light and heavy peptide populations. After protein extraction, enzymatic digestion, and LC-MS/MS analysis, differences in peptide signals between labeling states are used to calculate relative protein abundance changes. By combining metabolic labeling with high-resolution mass spectrometry, SILAC provides reproducible quantitative information for investigating protein expression changes in controlled cellular models.

Figure 1. Principles of SILAC

SILAC Proteomics Service at MtoZ Biolabs

MtoZ Biolabs provides SILAC-based quantitative proteomics analysis services for prepared SILAC-labeled samples.

SILAC samples are analyzed using high-resolution LC-MS/MS platforms with DDA acquisition strategies. The workflow supports peptide and protein identification, SILAC ratio calculation, differential protein analysis, and functional interpretation based on established proteomics analysis pipelines.

When This Service Is a Good Fit

SILAC-based proteomics is suitable for studies where:

• cultured cell models are used for controlled experimental comparison;
• protein abundance changes between different cellular conditions need to be quantified;
• biological responses after drug treatment or genetic perturbation need to be investigated;
• reduced technical variation during quantitative analysis is beneficial;
• relative protein expression profiling is required in isotope-labeled cellular systems.

For studies involving non-labeled samples, complex clinical cohorts, or larger multiplexed comparisons, alternative quantitative proteomics strategies such as TMT or label-free quantification may be considered.

Analysis Workflow

1. SILAC Sample Assessment

Prepared SILAC-labeled samples are evaluated based on labeling information, sample condition, and compatibility with LC-MS/MS analysis.

 

2. Protein Extraction and Digestion

Protein samples undergo extraction, reduction, alkylation, enzymatic digestion, and peptide preparation.

 

3. LC-MS/MS Acquisition

Prepared peptide samples are analyzed using high-resolution mass spectrometry with DDA acquisition to obtain peptide identification and quantitative information.

 

4. Quantitative Data Analysis

MS data are processed for peptide identification, SILAC ratio calculation, differential protein analysis, and downstream bioinformatics interpretation.

Sample Submission Requirements

1. Supported Sample Types

SILAC analysis accepts prepared labeled samples, including SILAC-labeled cell pellets, labeled cell lysates, and labeled protein samples.

 

2. Sample Amount and Concentration

For protein solution samples:

• Recommended total protein amount:>20 μg
• Recommended protein concentration:>0.5 μg/μL

Sample requirements may vary depending on sample type, complexity, and experimental design.

 

3. Storage and Shipping

• Cell pellet samples should be flash frozen and shipped on dry ice.
• Protein solution samples should be shipped frozen on dry ice.

Samples should be compatible with LC-MS/MS analysis and prepared with minimal interfering components such as high concentrations of SDS or salts.

Applications

1. Differential Protein Expression Analysis

SILAC enables quantitative comparison of protein abundance changes between experimental conditions, supporting identification of regulated proteins.

 

2. Cellular Response Studies

SILAC-based proteomics can be applied to investigate molecular responses following drug treatment, environmental stimulation, or genetic modification.

 

3. Signaling Pathway Research

Quantitative protein expression profiles generated by SILAC support investigation of pathway-associated molecular changes.

 

4. Mechanistic Proteomics Studies

SILAC provides quantitative proteome-level information for studying biological regulation in controlled cellular models.

 

Service Advantages

1. High-Resolution Mass Spectrometry Platform

MtoZ Biolabs applies high-resolution Orbitrap mass spectrometry platforms and optimized LC-MS/MS workflows for SILAC sample analysis.

 

2. Deep Protein Identification Capability

For typical cellular samples, SILAC workflows can achieve identification of more than 6,000 proteins under suitable analytical conditions.

 

3. High Mass Accuracy and Data Quality

High-resolution MS analysis provides mass accuracy typically within <5 ppm, supporting reliable peptide identification and quantitative analysis.

 

4. Comprehensive Data Interpretation

Integrated bioinformatics workflows provide protein identification, quantitative comparison, and functional analysis including GO, KEGG, and PPI-related interpretation when applicable.

 

Deliverables

1. Protein and Peptide Identification Results

Protein and peptide identification information generated from LC-MS/MS analysis.

 

2. SILAC Quantitative Results

Relative protein abundance ratios between different isotope-labeled conditions.

 

3. Differential Protein Analysis

Comparison of regulated proteins between experimental groups.

 

4. Functional Bioinformatics Analysis

Functional annotation and enrichment analysis including GO, KEGG, and PPI analysis when applicable.

 

5. Raw Mass Spectrometry Data

Original LC-MS/MS data files generated during analysis.

 

6. Final Report

Comprehensive analysis report summarizing identification, quantification, and biological interpretation results.

 

FAQ

Q1: What types of SILAC samples can be submitted?

Prepared SILAC-labeled cell pellets, labeled cell lysates, and labeled protein samples can be evaluated for SILAC proteomics analysis.

 

Q2: Can SILAC be applied to tissues or biological fluids?

SILAC is primarily designed for metabolically labeled cellular systems. For non-labeled samples such as tissues or biological fluids, alternative quantitative proteomics approaches such as TMT or label-free quantification may be considered.

 

Q3: How does SILAC compare with TMT quantification?

SILAC uses metabolic isotope labeling during cell culture, while TMT uses chemical labeling after sample preparation. The appropriate quantitative strategy depends on sample type, experimental design, and research objectives.

 

Q4: How long does a SILAC proteomics project usually take?

A typical SILAC proteomics project requires approximately 3–4 weeks, depending on sample number, sample preparation complexity, instrument scheduling, and data analysis requirements.

 

Contact Us

SILAC-based quantitative proteomics provides a robust approach for comparative protein expression analysis in isotope-labeled cellular systems.

Contact MtoZ Biolabs with your SILAC sample information and research objectives to establish an appropriate LC-MS/MS-based quantitative proteomics workflow.