| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject new variant enzyme having high activity and useful e.g. for the quality improvement in the treatment of meat and protein by substituting glycine at a specific position of subtilisin YaB produced by alkalophilic Bacillus YaB with other amino acid. SOLUTION: This new variant subtilisin YaB is produced by replacing the glycines at the 124, 151 and/or 159 sites of subtilisin YaB produced by alkalophilic Bacillus YaB with other amino acids. The enzyme has a substrate specificity different from that of wild-type subtilisin, exhibits improved relative elastin/casein hydrolysis activity and is useful e.g. for improving the quality of food such as the softening of meat, the quality of meat for feed and the quality of product in protein treating process. The variant can be produced by cloning ale gene from wild-type Bacillus subtilis YaB, inserting the gene into a vector, subjecting to site-specific mutagenesis to cause the mutation on the amino acid residues at prescribed sites of the gene product and expressing the gene. |
