A procedure of isolating a biologically active protein from the human mixed saliva was described. The acetone precipitate (S-precipitate) of the human saliva extracted with glacial acetic acid yielded E-precipitate by addition of ether. By purifying the E-precipitate a new strong biological active substance was isolated and named “Saliva-parotin-A”. The yield was 25 to 30mg per 100ml of mixed saliva.
