| 主权项 |
1. A method for making an isolated chymosin polypeptide variant comprising:
(a) producing a chymosin polypeptide variant having an alteration at one or more positions in its amino acid sequence relative to a parent polypeptide having chymosin activity, wherein the alteration comprises a substitution, a deletion or an insertion in at least one amino acid position corresponding to any of positions 117, 134, 141, 143, 156, 241, 279, 280, 281, 298, 300, 307, 309, 311, 325, 350, 352 and 353; and (b) isolating the polypeptide variant of step (a), thereby obtaining the isolated chymosin polypeptide variant, wherein the variant has chymosin activity; and wherein: (i): the amino acid position of the parent polypeptide is determined by an alignment of the amino acid sequence of the parent polypeptide with the amino acid sequence of the polypeptide of SEQ ID NO: 1 (bovine chymosin); and (ii): the parent polypeptide has at least 65% sequence identity with the mature polypeptide from amino acid position 59 to amino acid position 381 of SEQ ID NO: 1 (bovine chymosin). |
