Catalytic antibodies possess unique features capable of both recognizing and enzymatically degrading antigens. Therefore, they are more beneficial than monoclonal antibodies (mAbs). Catalytic antibodies exhibit the ability to degrade peptides, antigenic proteins, DNA, and physiologically active molecules. However, they have a significant drawback in terms of their production. The production of a desired catalytic antibody has extensive costs, in terms of time and effort. We herein describe an evolutionary method to produce a desired catalytic antibody via conversion of a general antibody by the deletion of Pro95, which resides in complementarity-determining region-3. As over thousands of mAbs have been produced since 1975, using the novel technology discussed herein, the catalytic feature cleaving the antigen can be conferred to the mAb. In this review article, we discussed in detail not only the role of Pro95 but also the unique features of the converted catalytic antibodies. This technique will accelerate research on therapeutic application of catalytic antibodies.

Gustatory and olfactory receptors receive multiple chemical substances of different types simultaneously, but they can barely discriminate one chemical species from others. In this article, we describe a device used to measure taste, i.e., taste sensors. Toko and colleagues developed a taste sensor equipped with multiarray electrodes using a lipid/polymer membrane as the transducer in 1989. This sensor has a concept of global selectivity to decompose the characteristics of a chemical substance into taste qualities and to quantify them. The use of taste sensors has spread around the world. More than 600 examples of taste-sensing system have been used, while providing the first “taste scale” in the world. This article explains the principle of taste sensors and their application to foods and medicines, and also a novel type of taste sensor using allostery. Taste-sensor technology, the underlying principle of which is different from that of conventional analytical instruments, markedly affects many aspects including social economy as well as the food industry.