The invention relates to the technical field of
enzyme engineering, and discloses an aminotransferase
mutant and application thereof. The invention provides a
wild type amino
transferase mutant which is derived from
Aspergillus avenaceus (
Aspergillus avenaceus), and a preparation method of the amino
transferase mutant. The amino
transferase mutant is obtained by carrying out single-site or multi-site combined
mutation on the 20th site, the 60th site, the 92nd site and the 186th site of an
amino acid sequence as shown in SEQ ID NO.2. As a biocatalyst,
sitagliptin intermediate precursor
ketone can be directly used as a substrate,
isopropylamine is used as an amino donor,
pyridoxal phosphate is used as a coenzyme,
dimethyl sulfoxide is used as a substrate cosolvent, and the amino transferase mutant is obtained by carrying out single-site or multi-site combined
mutation on the 20th site, the 60th site, the 92nd site and the 186th site of the
amino acid sequence as shown in SEQ ID NO.2. The
Sitagliptin intermediate with high optical purity is prepared through
catalysis, the
specific enzyme activity reaches 139.3 U / g in a
reaction system with the DMSO volume final concentration being 50%, the
catalysis efficiency is greatly improved, and the product has high
stereoselectivity (the e.e. Value of the product reaches 99%) and has wide industrial application prospects.