Improvement of the Signal-to-noise Ratio on the Fluorescent Detection of a Membrane Protein Using Horse Radish Peroxidase

Horseradish peroxidase (HRP) is used as a sensitizing enzyme to detect a membrane protein with high sensitivity. In this method, the membrane protein is labeled with HRP, and fluorescent group-modified tyramide is used as a substrate for fluorescent signal amplification. However, a high background signal due to a nonspecific adsorption of fluorescent group-modified tyramide to cells is known to compromise high-sensitive detection. Here, we designed a new substrate in which tyramide was changed to tyrosyltaurine. Because the background signal was greatly reduced by the sulfonate group in the new substrate, the signal-to-noise ratio was greatly improved compared with a commercial substrate.