Publication Date: 2005-Dec-27
The IP.com Prior Art Database
Alpha-amylase variants with altered properties
FIELD OF THE INVENTION
The present invention relates to variants (mutants) of parent Termamyl-like alpha-amylases, which variant has alpha-amylase activity and exhibits an alteration in at least one of the following properties relative to said parent alpha-amylase: Substrate specificity, substrate binding, substrate cleavage pattern, thermal stability, pH activity profile, pH stability profile, stability towards oxidation, Ca2+ dependency, reduced and increased pI and improved wash performance, specific activity, stability under, e.g., high temperature and/or low/high pH conditions, in particular at low calcium concentrations, and stability in the presence of detergent, e.g. storage stability in the detergents. The variant of the invention are suitable for starch conversion, ethanol production, laundry wash, dish wash, hard surface cleaning, textile desizing, and/or sweetner production.
BACKGROUND OF THE INVENTION
Alpha-Amylases (alpha‑1,4-glucan‑4‑glucanohydrolases, E.C. 220.127.116.11) constitute a group of enzymes, which catalyze hydrolysis of starch and other linear and branched 1,4‑glucosidic oligo‑ and polysaccharides.
The object of the invention is to provide an improved alpha-amylase, in particular suitable for detergent use.
SUMMARY OF THE INVENTION
The object of the present invention is to provide Termamyl-like amylases which variants in comparison to the corresponding parent alpha-amylase, i.e., un-mutated alpha-amylase, has alpha-amylase activity and exhibits an alteration in at least one of the above properties relative to said parent alpha-amylase.
In the present description and claims, the conventional one-letter and three-letter codes for amino acid residues are used. For ease of reference, alpha-amylase variants of the invention are described by use of the following nomenclature:
Original amino acid(s): position(s): substituted amino acid(s)
According to this nomenclature, for instance the substitution of alanine for asparagine in position 30 is shown as:
Ala30Asn or A30N
a deletion of alanine in the same position is shown as:
Ala30* or A30*
and insertion of an additional amino acid residue, such as lysine, is shown as:
Ala30AlaLys or A30AK
A deletion of a consecutive stretch of amino acid residues, such as amino acid residues 30-33, is indicated as (30-33)* or D(A30-N33).
Where a specific alpha-amylase contains a "deletion" in comparison with other alpha-amylases and an insertion is made in such a position this is indicated as:
*36Asp or *36D
for insertion of an aspartic acid in position 36.
Multiple mutations are separated by plus signs, i.e.: