SIALIC ACID COMBINED POLYPEPTIDE MIXTURE HAVING HIGH CONCENTRATION OF SIALIC ACID

摘要

PURPOSE: A sialic acid combined polypeptide mixture having high concentration of sialic acid is provided, thereby cheaply and simply preparing the sialic acid combined polypeptide. CONSTITUTION: A process for preparing a sialic acid combined polypeptide mixture comprises the steps of: digesting the defatted yolk with alkaliphilic endoprotease to prepare peptide fragments; digesting the peptide fragments with slightly alkali endoprotease to prepare peptides; digesting the peptides with exoprotease; and filtering the peptides formed by the endo- and exo-hydrolysis with a 2,000 to 5,000 dalton of ultrafiltration membrane, wherein the endoprotease in the first endo hydrolysis is isolated from Bacillus subtilis; the exoprotease in the exo hydrolysis is isolated from Aspergillus oryzae; and the endoprotease in the second endo hydrolysis is isolated from Bacillus subtilis.