GLUCOSE ISOMERASE MUTANTS, THE USE THEREOF AND THE DNAS ENCODING THE SAME

摘要

This invention provides a series of recombinant Thermoanaerobacterium saccharolyticum glucose isomerases with improved catalytic activity and thermostability obtained by using recombinant techniques. These recombinant glucose isomerases comprise amino acid variation including phenylalanine (Phe) at position 139, alanine (Ala) at position 182, serine (Ser) at position 187, and glutamine (Gln) at position 299, and carry at least one additional mutated amino acid at position 87, position 217, position 260 or position 276, and possess a higher catalytic activity than that of the wild-type when using D-glucose as substrate. These recombinant glucose isomerases can be used for direct production of high fructose corn syrup containing 55.% [wt] or higher concentration of fructose.