Organic chemistry for creation and regulation of protein functions

In recent years, a variety of chemical methods for selective labeling or functional modulation of protein of interest has been developed. In this article, we focus on synthetic organic chemistry for protein modification, especially on the recent developments of the bioorthogonal reactions, which enable to hybridize an artificial small molecule to a protein of interest with a site-selective manner. On the other hand, covalent bond formation of protein with a small molecule has also been recognized as a powerful strategy to regulate protein functions, and enormous efforts have been devoted to develop selective irreversible inhibitors for proteins, especially for the families of proteases, in the research field of medicinal chemistry. We also provide an overview of the irreversible inhibitors, including their recent advancements and some applications for proteome analysis or drug discovery. In addition, we report herein our original method (P-PALM) for site-selective modification of a protein using the photo-affinity labeling technique. The utility of the P-PALM method has been successfully demonstrated in the modifications of the lectin into the new fluorescent saccharide biosensors.