The present invention provides novel esterase proteins, Specifically, the present invention provides proteins having the same or substantially the same amino acid sequence as the amino acid sequence represented by SEQ ID NO: 1 or SEQ ID NO: 7, or salts thereof; their partial peptides or salts thereof: DNAs encoding the proteins; recombinant vectors containing the DNAs; transformants, a method of manufacturing the proteins; pharmaceuticals comprising the proteins or DNAs; antibodies to the proteins; a method of screening compounds or salts thereof having an activity of promoting the esterase activity of the proteins; the compounds obtained by the screening; and pharmaceuticals comprising the said compounds; etc.