Signal Amplification Enzymes for Bioanalysis of Cells and Tissues

In bioanalysis, where proteins in biological samples are labeled with antibodies for detection, enzymatic sensitization reactions are used to enhance the detection signal derived from the dye. In this review, we discussed the desired properties of sensitizing enzymes for bioanalysis and showed that the three conventionally used sensitizing enzymes (horseradish peroxidase, alkaline phosphatase, and β-galactosidase) satisfy these requirements. At the same time, we described the viewpoint calling attention to a lack of conventional enzymes and proposed “mammalian orthogonal enzymes” as a new class of sensitizing enzymes incorporating this viewpoint, and introduced our discovery of α-arabinofuranosidase as an example. If multiple enzymes of this new class are prepared, multi-color detection of multiple antigens will be possible, which is expected to greatly enhance the usefulness of bioanalysis.