Unlabeled Quantification: Application of Label-Free Quantification

In the field of biopharmaceutical research, understanding the quantitative information of proteins is crucial to understanding cellular processes and disease mechanisms. In recent years, label-free quantification has emerged, providing researchers with a more accurate and flexible method of protein quantification.

 

Label-free quantification is based on the principle of mass spectrometry, inferring the relative abundance of proteins by measuring the intensity of peptide characteristic peaks in protein samples. This method does not require the use of any label molecules, thus avoiding biases and interferences introduced by labeling. Label-free quantification mainly includes two methods: library-based quantification and peak area-based quantification.

 

1. Library-Based Quantification

Library-based quantification is determined by comparing with known protein spectra to determine the relative abundance of proteins in the test sample. This method requires the establishment of a database containing known protein spectra and comparing the spectrums of the test sample with the database. Through comparative analysis, the relative abundance of proteins in the test sample can be determined.

 

2. Peak Area-Based Quantification

Peak area-based quantification is to infer the relative abundance of proteins by measuring the area of peptide characteristic peaks in protein samples. This method uses a mass spectrometer to measure the intensity of peptide characteristic peaks and calculate the peak area. By comparing the area of peptide characteristic peaks in different samples, the relative abundance of proteins can be determined.

 

Advantages of Label-Free Quantification

Compared with traditional labeled quantification methods, label-free quantification has the following advantages:

 

1. High Sensitivity

Label-free quantification uses mass spectrometry, which has high sensitivity and high resolution. It can detect low-abundance proteins and provide accurate quantification results.

 

2. High Accuracy

Label-free quantification avoids biases and interferences introduced by labeling, providing more accurate quantification results. It can accurately measure the relative abundance of proteins, helping researchers to better understand cellular processes and disease mechanisms.

 

3. Flexibility

Label-free quantification does not require the use of specific labeling molecules, giving it greater flexibility. Researchers can choose the appropriate mass spectrometry analysis method according to experimental needs, thus achieving more accurate quantification.

 

Applications of Label-Free Quantification

Label-free quantification technology has a wide range of applications in biopharmaceutical research. Below are some common application fields:

 

1. Proteomics Research

Label-free quantification can be used for the study of proteomics, helping researchers understand the expression and regulation of proteins in cells. By comparing the relative abundance of proteins in different samples, disease-related protein biomarkers can be discovered, providing a basis for early diagnosis and treatment of diseases.

 

2. Drug Development

Label-free quantification can be used for drug efficacy evaluation and drug metabolism research in drug development. By measuring the protein binding situation of drugs in the body and the relative abundance of metabolites, the efficacy and safety of drugs can be evaluated.

 

3. Biomarker Discovery

Label-free quantification can be used for the discovery and verification of biomarkers. By comparing the relative abundance of proteins in diseased tissues and normal tissues, disease-related protein biomarkers can be discovered, providing new targets for the diagnosis and treatment of diseases.