What Is Protein Quantification Assay?
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Orbitrap (Thermo series): Offers high resolution and sensitivity, and is widely used for peptide quantification;
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Q Exactive series: Supports parallel reaction monitoring (PRM), ideal for high-throughput targeted quantification;
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TripleTOF (SCIEX): Employs data-independent acquisition (DIA), providing high efficiency for proteome profiling.
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A flexible portfolio of quantification strategies across multiple platforms, including Label-Free, TMT, and MRM
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Broad compatibility with diverse sample types, ranging from human, animal, and microbial to plant and exosomal sources
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End-to-end quality control (QC) and expert bioinformatics support
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Seamless integration with multi-omics approaches, including metabolomics, transcriptomics, and phosphoproteomics
Protein quantification refers to the process of measuring the amount or relative abundance of proteins in a given sample. This assay plays a crucial role in proteomics, biomarker discovery, and elucidation of drug mechanisms. By quantifying protein expression under different conditions, researchers can gain deeper insights into cellular function, disease progression, and therapeutic responses.
Main Types of Protein Quantification Assays
1. Total Protein Quantification
This is the most fundamental form of protein quantification assay, designed to determine the total protein content within a sample. It is often used for sample normalization or as a preparatory step prior to further experimental procedures. Common methods include:
(1) BCA Assay (Bicinchoninic Acid Assay): Highly sensitive to protein concentration and compatible with a wide range of sample types.
(2) Bradford Assay: Rapid and efficient, though its accuracy may be compromised in the presence of certain buffer components, such as SDS.
(3) Lowry Assay: Offers high sensitivity, but involves relatively complex procedures.
2. Relative Quantification
This approach is used to compare the expression levels of a specific protein across different samples, such as between control and experimental groups. The main strategies include:
(1) Label-based Mass Spectrometry Techniques (e.g., TMT, iTRAQ): Employ isotopic tags for simultaneous analysis of multiple samples, offering high precision.
(2) Label-Free Quantification: Does not require chemical labeling and is particularly suitable for large-scale screening across extensive sample sets.
3. Absolute Quantification
In contrast to relative quantification, absolute quantification aims for higher precision by determining the exact concentration of a target protein in a sample using standards (peptides or proteins) of known concentrations. The results are typically expressed in units such as ng/mL or copy number. Commonly used methods include:
(1) AQUA (Absolute QUAntification): Utilizes synthetically produced stable isotope-labeled peptides as internal standards, suitable for targeted protein validation;
(2) QconCAT: Constructs artificial proteins by concatenating multiple peptide sequences, enabling simultaneous quantification of multiple target proteins;
(3) Standard Curve Method: Establishes a correlation between standard concentrations and peak areas to indirectly calculate the concentration of the target protein.
For high-accuracy applications such as clinical biomarker validation and drug target screening, MtoZ Biolabs offers targeted MRM/SRM/PRM-based protein quantification services, enabling absolute quantification of single or multiple proteins. The results can serve as supporting data for regulatory submissions.
Selection of Mass Spectrometry Platforms for Protein Quantification Assay
Modern protein quantification has entered the era of high-resolution mass spectrometry (HRMS). Leading platforms include:
MtoZ Biolabs is equipped with multiple Orbitrap Fusion Lumos and Q Exactive HF-X instruments, integrated with automated sample preparation systems and AI-based data analysis algorithms, ensuring high reproducibility, broad proteome coverage, and low variability in quantification results.
Application Scenarios: Scientific and Industrial Value of Protein Quantification Assay
Protein quantification plays a critical role not only in basic research but is also increasingly applied across various industrial sectors including biomedicine, agriculture, environmental science, and synthetic biology.
1. Investigation of Disease Mechanisms
Enables comparative analysis of protein expression profiles between healthy and diseased states, facilitating the identification of regulatory networks, key enzymes, and inflammatory mediators.
2. Drug Development and Mechanistic Studies
Monitors changes in protein expression before and after treatment to identify potential therapeutic targets and elucidate drug action pathways.
3. Clinical Biomarker Discovery
Integrates proteomics with metabolomics and transcriptomics to identify clinically relevant protein biomarkers for early diagnosis or prognosis.
4. Synthetic Biology and Metabolic Engineering
Quantifies the expression of key enzymes in synthetic pathways to enhance product yield and enable precise control of metabolic flux.
Advantages of MtoZ Biolabs' Quantitative Protein Services
We are committed to providing our clients with comprehensive protein quantification solutions that offer high coverage, high accuracy, and excellent cost-effectiveness:
Protein quantification assay is not merely a technical procedure but a scientific methodology for gaining profound insights into biological systems. With the continuous advancement of mass spectrometry and data analytics, it is playing an increasingly vital role in frontier fields such as precision medicine, molecular diagnostics, and synthetic biology. If your research involves protein expression profiling, biomarker discovery, mechanistic investigations, or drug efficacy evaluation, we welcome you to collaborate with MtoZ Biolabs. Our professional platforms and services are here to fully support your scientific endeavors.
MtoZ Biolabs, an integrated chromatography and mass spectrometry (MS) services provider.
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