Fluorescent-labeled protein is a powerful tool for the detection of CAR expression in research and clinical samples by flow cytometry. These proteins are pre-labeled fluorescent dyes that can detect CAR expression by one-step staining with minimal background. However, the development of high-quality fluorescent-labeled proteins presents a major challenge and there are only few products commercially available so far.

 

Conjugation technique is a major bottleneck for developing high-quality fluorescent-labeled proteins. Currently, the most widely used labeling technique in the market is the traditional chemical labeling approach. It is a very easy method to covalently label protein with a fluorescent dye in a non-specific manner. However, random modification can lead to heterogeneous and may affect the bioactivity of the protein via blocking the protein-active site.

 

Studies indicate that the new-generation site-specific labeling technology can attach fluorescent dyes to specific protein in site-specific manner. It provides a guarantee to the uniformity of the fluorescent-labeled products and avoids affecting protein activity. This property makes it a useful weapon for the development of high-quality fluorescent-labeled protein products with high specificity and sensitivity.