Of casein - beta a process for the preparation of fractions, which are enriched with biologically active peptides as well as the resulting peptide fractions.

摘要

In order to obtain, from casein beta , a partial hydrolyzate enriched with, firstly, a phosphopeptide or a 1-25 peptide fraction, and, secondly, precursors of beta -casomorphine (these precursors being fragments which cover the 33-97 region of the casein beta molecule), by hydrolyzing the casein beta with a proteolytic enzyme, the hydrolysis is carried out in a saline medium, thereby causing a precipitate to appear in the medium and separating it from the soluble phase which represents the partial hydrolyzate desired. Preferably, this hydrolysis is carried out in a medium of which the ionic strength is equivalent to that of a solution of monovalent salt having an ionic strength of between 0.5 and 4M. In order to obtain the 1-25 peptide fraction and the precursors of beta -casomorphine, ion exchange chromatography is carried out on this soluble phase, after having demineralized it by electrodialysis. In order to obtain the antihypertensive and immunostimulatory 177-183 peptide fraction, the precipitate obtained is made soluble, the resulting solution is brought to a pH level of between 6 and 9, and hydrolysis is carried out by means of a proteolytic enzyme.