Unlabeled Quantitative Proteomics

Label-free Quantitative Technology is one of the methods for studying quantitative proteomics. Compared to traditional labeling quantitative methods, label-free quantitative protein technology has significant advantages. Traditional labeling methods usually involve complex experimental steps, which are time-consuming and laborious, and the cost of labeling reagents is high. However, label-free quantification technology does not require special experimental operations, eliminates the cumbersome labeling steps, and makes the experimental process more concise and efficient. Moreover, the cost of this technology is relatively low and sample preparation is relatively simple. Currently, the most widely used non-labeled quantitative methods are mainly two types, one is based on the peak area or peak intensity of the mass spectrum to perform quantification, and the other is based on the identification number of protein peptides for quantification.

 

Quantitation Based on the Peak Area or Peak Intensity of Mass Spectra

The principle is based on the correlation between the peptide mass spectrometry signal and its content. By comparing the peak area or peak intensity of the same peptide in different samples, the relative content of the peptide in different samples can be calculated. This method is also known as the ion intensity method or signal intensity method.

 

Quantitation Based on the Identification Number of Protein Peptides

After higher abundance proteins are digested, the visibility of their generated peptides in mass spectrometry detection is enhanced, and the probability of detection is greatly increased. Based on this principle, it can be observed that there is a significant positive correlation between the abundance of proteins and the identification number of peptides produced after digestion. Therefore, relative quantification of proteins can be achieved by comparing the number of identified peptides of proteins in different samples.

 

Applications

Label-free technology is particularly suitable for analyzing samples with low complexity, such as Co-IP, pull-down, subcellular components, DARTS samples, etc. In these cases, the technology can provide accurate and efficient protein quantification results. In addition, it is often used for quantitative comparison of large sample volumes and experimental designs that cannot be achieved with labeled quantification.

 

MtoZ Biolabs uses Thermo Fisher's Q ExactiveHF mass spectrometry platform combined with Nano-LC chromatography to provide fast and accurate label-free quantitative proteomics analysis services. You only need to tell us your experimental purpose and send your cells to us, and we will be responsible for all subsequent matters of the project, including cell culture, cell labeling, protein extraction, protein digestion, peptide separation, mass spectrometry analysis, mass spectrometry raw data analysis, and bioinformatics analysis. Feel free to inquire.