Polypeptide

A nucleic acid sequence derivable from a parent sequence, the parent sequence capable of encoding a non-maltogenic exoamylase, which nucleic acid sequence comprises a substitution at one or more residues such that the nucleic acid encodes one or more of the following mutations at the positions specified:

• (a) 121F, 121Y, 121W, 161A, 223E, 223K;
• (b) 146G, 146M, 157M, 158T, 158A, 158S, 198W, 198F, 229P, 303E, 303D, 306T, 306G, 309P, 316S, 316P, 316K, 316Q, 353T;
• and (c) 26E, 70D, 1145D, 188S, 188T, 188H, 272Q, 339A, 339E;
• with reference to the position numbering of a Pseudomonas saccharophilia exoamylase sequence shown as SEQ ID NO:
• 1.

A method of altering the sequence of a polypeptide by introducing an amino acid substitution selected from the group consisting of:

• (a) 121F, 121Y, 121W, 161A, 223E, 223K;
• (b) 146G, 146M, 157M, 158T, 158A, 158S, 198W, 198F, 229P, 303E, 303D, 306T, 306G, 309P, 316S, 316P, 316K, 316Q, 353T;
• and (c) 26E, 70D, 1145D, 188S, 188T, 188H, 272Q, 339A, 339E (with reference to the position numbering of a Pseudomonas saccharophilia exoamylase sequence shown as SEQ ID NO:
• 1), into a parent polypeptide having non-maltogenic exoamylase activity.

A method of producing a PS4 polypeptide variant, the method comprising introducing an amino acid substitution into a parent polypeptide having non-maltogenic exoamylase activity, the amino acid substitution being selected from the group consisting of:

• (a) 121F, 121Y, 121W, 161A, 223E, 223K;
• (b) 146G, 146M, 157M, 158T, 158A, 158S, 198W, 198F, 229P, 303E, 303D, 306T, 306G, 309P, 316S, 316P, 316K, 316Q, 353T;
• and (c) 26E, 70D, 1145D, 188S, 188T, 188H, 272Q, 339A, 339E with reference to the position numbering of a Pseudomonas saccharophilia exoamylase sequence shown as SEQ ID NO:
• 1.

A method of altering the sequence of a nucleic acid encoding a non-maltogenic exoamylase, the method comprising introducing into the sequence a codon which encodes an amino acid residue selected from the group consisting of:

• (a) 121F, 121Y, 121W, 161A, 223E, 223K;
• (b) 146G, 146M, 157M, 158T, 158A, 158S, 198W, 198F, 229P, 303E, 303D, 306T, 306G, 309P, 316S, 316P, 316K, 316Q, 353T;
• and (c) 26E, 70D, 1145D, 188S, 188T, 188H, 272Q, 339A, 339E, with reference to the position numbering of a Pseudomonas saccharophilia exoamylase sequence shown as SEQ ID NO:
• 1.