NEW MATERIAL:A peptide expressed by the formula.

USE: An anticarious agent and remedy.

PREPARATION: For example, a rat parotoid gland is minced, and cooled acetone is added thereto. The resultant mixture is stirred while cooling and filtered to remove the acetone by air drying and vacuum drying and give acetone-dried powder. Water is then added to carry out extraction. The resultant extract is then centrifuged and separated into precipitate and supernatant. Hydrochloric acid is then added to the supernatant to adjust the pH to 5, and the deposited precipitate is removed by centrifugation. The pH of the supernatant is then adjusted to 7.0. The solution is concentrated under reduced pressure and filtered through an ultrafiltration membrane for 30,000 fractionated molecular weight. The resultant filtrate is desalted and eluted with a sephadex G-10 column to concentrate the eluate. The concentrated eluate is then subjected to gel filtration with a sephadex LH-20 column to afford a fraction having 1,000W3,500 fractionated molecular weight, which is then subjected to electrophoresis and desalted with an ultrafiltration membrane to give the aimed peptide expressed by the formula.