The present invention provides target proteins and target genes for bioactive substances such as drugs, and means that enable the development of novel bioactive substances using the same. More specifically, the present invention provides target proteins and target genes for bioactive substances; screening methods for substances capable of regulating bioactivities; bioactivity regulators; a bioactive substance derivative production method; a complex comprising a bioactive substance and a target protein, and a method of producing the complex; and kits comprising a bioactive substance or a salt thereof; determination methods for the onset or risk of onset of a specified disease or condition, determination methods for susceptibility to a bioactive substance, and determination kits used for the determination methods, and the like.