| abstract |
We describing can derived from the PS4 variant polypeptides of parent polypeptide with non-maltose exo-amylase enzymic activity, wherein said PS4 variant polypeptides comprises 307 amino acid replacing with Methionin (K) or arginine (R) and replaces, and shown in reference SEQ ID NO:1, Pseudomonas saccharophila exo-amylase enzyme sequence is position encoded.This PS4 variant polypeptides preferably comprises 70 further, and the amino acid of preferred G70D is replaced.The amino acid of sequence 272 and 303 is preferably Histidine (H) and glycine (G). |