公开(公告)号：US07049122B2

公开(公告)日：2006-05-23

申请号：US10233443

申请日：2002-09-04

Applicant: Rey-Chang Chang ,  Shu-Jen Chou ,  Jei-Fu Shaw

Inventor： Rey-Chang Chang ,  Shu-Jen Chou ,  Jei-Fu Shaw

IPC: C12N9/20

CPC classification number: C12N9/18 ,  C12N9/20 ,  C12Y301/01003

Abstract: The present invention provides mutant-type lipases which demonstrate superior lipolytic and esterific activities. The mutant-type lipases are characterized by an amino acid alteration at the residue immediately followed either the serine residue or the histidine residue or both residues of the Ser-His-Asp catalytic triad. The Ser-His-Asp catalytic triad is known to be the three residues, although occur far apart in the amino acid sequence of a lipase, that contribute to the hydrolytic activity in the active site of the lipase. The amino acid residue that follows the serine residue of the Ser-His-Asp catalytic triad is alanine. The amino acid residue that follows the histidine residue of the Ser-His-Asp catalytic triad is isoleucine. The wild-type lipase is preferably originated from Staphylococcus, particularly Staphylococcus epidermindis. The present invention also relates to a method for preparing the mutant-type lipases by site-directed mutagenesis using PCR and a method for utilizing the mutant-type lipase to catalyze synthesis of flavor esters to be used in food industry.