Label-free quantification is a method of determining the relative amount of proteins in two or more biological samples, but unlike other quantitative methods, it does not use a stable isotope for chemical binding and labeling of proteins. Label-free quantitative proteomics approach provides a powerful tool to resolve and identify thousands of proteins from a complex biological sample. In this approach, proteins are first digested with a protease into a peptide mixture, which is subsequently analyzed by tandem MS (MS/MS) and identified by database searching. Relative protein abundance is determined by either spectral counting or chromatographic peak intensity measurements. Compared with other proteomic methods, the label-free quantification approach is rapid and more sensitive, which increases the protein dynamic range 3- to 4-fold as compared to 2DE. This method can also be automated with the ability for large-scale proteome analysis.
Label-free method for quantitation is very popular in proteomics community and may be the most straight-forward laboratory technique in the field. We summarize the pros and cons as follows:
|Wet lab complexity time||little||medium|
|Comparability of samples||difficult||easy|
Our services enable the quantitative and qualitative analysis of complex samples such as cell lysates, tissue homogenates or bio-fluids. The results from this experiment provide a catalogue of the proteins present in all samples and a statistical analysis reflecting the changes in protein levels observed across the samples, along with relevant pathway information. Creative Proteomics' label-free quantification services consist of the following four fundamental steps:
Figure 1. A typical workflow chart for LC/MS-based label-free protein quantification.
Creative Proteomics can provide label-free quantification services in a time-saving and cost-efficient manner. Whatever your protein analysis need is, analysis of entire proteomes or quantification of specific proteins, Creative Proteomics has the right solution for you. With our advanced platform and experienced staff, we can accelerate your research about protein quantification, please feel free to contact us.