Alpha-amylase Mutants
The invention relates to a variant of a parent Termamyl-like α-amylase, which exhibits an alteration in at least one of the following properties relative to said parent α-amylase: i) improved pH stability at a pH from 8 to 10.5; and/or ii) improved Ca 2+ stability at pH 8 to 10.5, and/or iii) increased specific activity at temperatures from 10 to 60° C.
1 . A variant alpha-amylase of a parent alpha-amylase, wherein the variant has alpha-amylase activity, and at least 95% homology with the amino acid sequence shown in SEQ ID. NO. 3 comprising one or more of the following substitutions (using SEQ ID NO: 3 for numbering):
I181A,R,N,C,E,Q,G,H,L,K,M,F,P,S,T,W,Y, or V, wherein the variant has increased specific activity relative to the parent alpha-amylase, wherein specific activity is determined at a temperature of 10° C. to 60° C.
2 . A variant alpha-amylase of a parent alpha-amylase, wherein the variant has alpha-amylase activity, and wherein the variant has at least 97% homology with SEQ ID. NO. 3 comprising one or more of the following substitutions (using SEQ ID NO: 3 for numbering):
I181A,R,N,C,E,Q,G,H,L,K,M,F,P,S,T,W,Y, or V, wherein the variant has increased specific activity relative to the parent alpha-amylase when determined at a temperature of 10° C. to 60° C.
3 . The variant of claim 2 , wherein the variant comprises a substitution of I181A.
4 . The variant of claim 2 , wherein the variant comprises a substitution of I181R.
5 . The variant of claim 2 , wherein the variant comprises a substitution of I181N.
6 . The variant of claim 2 , wherein the variant comprises a substitution of I181C.
7 . The variant of claim 2 , wherein the variant comprises a substitution of I181E.
8 . The variant of claim 2 , wherein the variant comprises a substitution of I181Q.
9 . The variant of claim 2 , wherein the variant comprises a substitution of I181G.
10 . The variant of claim 2 , wherein the variant comprises a substitution of I181H.
11 . The variant of claim 2 , wherein the variant comprises a substitution of I181L.
12 . The variant of claim 2 , wherein the variant comprises a substitution of I181K.
13 . The variant of claim 2 , wherein the variant comprises a substitution of I181M.
14 . The variant of claim 2 , wherein the variant comprises a substitution of I181F.
15 . The variant of claim 2 , wherein the variant comprises a substitution of I181P.
16 . The variant of claim 2 , wherein the variant comprises a substitution of I181S.
17 . The variant of claim 2 , wherein the variant comprises a substitution of I181T.
18 . The variant of claim 2 , wherein the variant comprises a substitution of I181W.
19 . The variant of claim 2 , wherein the variant comprises a substitution of I181Y.
20 . The variant of claim 2 , wherein the variant comprises a substitution of I181V.
21 . A variant alpha-amylase of a parent alpha-amylase, which variant has alpha-amylase activity and at least 95% homology with the amino acid sequence shown in SEQ ID. NO. 3, comprising a substitution (using SEQ ID NO: 3 for numbering):
at position 181, wherein the variant has increased specific activity relative to the parent alpha-amylase, wherein the specific activity is determined at a temperature of 20° C. to 50° C.
22 . A variant of a parent alpha-amylase, which variant has alpha-amylase activity, has at least 95% homology with the amino acid sequence shown in SEQ ID. NO. 3, comprising a substitution (using SEQ ID NO: 3 for numbering):
at position 181,
wherein the variant has increased specific activity relative to the parent alpha-amylase, wherein the specific activity is determined at a temperature of 30° C. to 40° C.
23 . The variant of claim 2 , wherein the variant has at least 99% homology with SEQ ID. NO. 3.