For past decades, lots of synthetic and botanical drugs have been clinically used but their exact modes of action in the molecular (protein) level remain largely unknown. Given that thousands of novel chemicals and related drugs have emerged in the drug discovery area, elucidation of the detailed interaction between a small molecule and the specific target protein is significantly important in order to avoid their side effects as well as positioning theirs appropriate clinical uses. The KIM lab has focused on the target identification of biologically active compounds such as natural products, based on chemoproteomic approaches. In order to succeed the target identification of chemicals, we mainly synthesize novel affinity or activity based chemical probes for the identification, and make close collaborations with molecular biology teams and proteomics teams. In addition, in an effort to provide a novel therapeutic strategy on the basis of chemical biology, we are trying to chemically knock down specific target proteins.