POLYPEPTIDE MIXTURE OF HIGH GLUTAMINE/GLUTAMINIC ACID CONTENT AND PROCESS FOR PRODUCING THE SAME

摘要

A polypeptide abundantly containing not only acidic amino acids such as glutaminic acid but also basic amino acids such as lysine and being appropriate in amino acid balance, the polypeptide exhibiting amphipathic property of being soluble in not only water but also an alcohol while having a relatively high molecular weight, is produced from a protein feedstock soluble in water. In particular, there is provided a process for producing a polypeptide mixture enriched in acidic and basic amino acids, characterized in that a soybean protein feedstock is subjected to zymolysis in a water system with the use of an endoprotease of low specificity while maintaining an alkali region; subsequently polypeptides of high hydrophobic amino acid content are removed as precipitate; and thereafter an alcohol is added thereto to thereby obtain a precipitate fraction.