Starch debranching enzymes
AssigneeNovozymes A/S
InventorsHenrik Bisgard-Frantzen, Allan Svendsen
Life of this patent
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Abstract
The invention relates to a genetically engineered variant of a parent starch debranching enzyme, i.e. a pullulanase or an isamylase, the enzyme variant having an improved thermostability at a pH in the range of 4-6 compared to the parent enzyme and/or an increased activity towards amylopectin and/or glycogen compared to the parent enzyme, to methods for producing such starch debranching enzyme variants with improved thermostability and/or altered substrate specificity, and to a method for converting starch to one or more sugars using at least one such enzyme variant.
Claims35
A genetically engineered variant of a parent starch debranching enzyme, the enzyme variant having an improved thermostability at a pH in the range of 4-6 compared to the parent enzyme.
A genetically engineered variant of a parent starch debranching enzyme, the enzyme variant having an increased activity towards amylopectin and/or glycogen compared to the parent enzyme.
A method for producing a starch debranching enzyme variant with increased thermostability, the method comprising the steps of:
- identifying one or more amino acid residues and/or amino acid regions associated with thermostability in a first parent starch debranching enzyme,
- identifying one or more homologous amino acid residues and/or amino acid regions in a second parent starch debranching enzyme by means of alignment of the amino acid sequences of the first and second parent starch debranching enzymes, and
- mutating one or more of the homologous amino acid residues and/or amino acid regions in the second parent starch debranching enzyme to produce an enzyme variant with increased thermostability.
A method for producing a starch debranching enzyme variant with altered substrate specificity, the method comprising the steps of:
- identifying one or more amino acid residues in at least one amino acid loop associated with specificity towards a desired substrate in a first parent starch debranching enzyme,
- identifying one or more homologous amino acid residues in at least one corresponding loop in a second parent starch debranching enzyme by means of alignment of the amino acid sequences of the first and second parent starch debranching enzymes, and
- mutating one or more of the homologous amino acid residues in at least one loop in the second parent starch debranching enzyme to produce an enzyme variant with altered substrate specificity.
Dependencies are inferred from the claim text.