PURIFICATION OF PEPTIDE-INCLUDING LIQUID

摘要

PROBLEM TO BE SOLVED: To purify a peptide-including liquid by subjecting a supernatant of a culture solution including a specific peptide after lactic acid fermentation or the like to electrodialysis treatment using a specific anion-exchange membrane and by efficiently removing ions except the above peptide in a short time while controlling the permeation of the peptide so as to become as little as possible. SOLUTION: A supernatant obtained by solid-liquid separation of a culture solution including an angiotension-conversion-enzyme inhibiting peptide obtained by cultivating lactic acid bacteria (or lactic acid bacteria and yeast), preferably after being concentrated, is treated by electrodialysis using anion-exchange membrane having a diffusion coefficient of (3.0-9.0)×10-6 [preferably (5.0-7.0)×10-6] preferably at room temperature to ca. 50 deg.C for ca. 3-10 h. The angiotension-conversion-enzyme inhibiting peptide is useful as a medicine having antihypertensive action and functional food. A cation-exchange membrane used in the above electrodialysis has e.g. a diffusion coefficient of (3.0-5.0)×10-6.