Gist-Brocades N.v.

Plant Genetic Systems N.v.

Anne-Marie Lambeir

Jan Metske Van Der Laan

Ignace Lasters

Wilhelmus J Quax

Onno Misset

Nadir Mrabet

Wilhemus J Quax

A method for selecting amino acid residues is disclosed which upon replacement will give rise to an enzyme with an altered pH optimum. The method is specific for metalloenzymes which are inactivated at low pH due to the dissociation of the metal ions. The method is based on altering the pK.sub.a of the metal coordinating ligands or altering the K.sub.ass for the metal binding. New glucose isomerases with an altered pH optimum are provided according to this method. These altered properties enable starch degradation to be performed at lower pH values.

Glucose isomerases with an altered pH optimum

Modified prokaryotic glucose isomerase enzymes with altered pH activity

A method for selecting amino acid residues is disclosed which upon replacement will give rise to an enzyme with an altered substrate specificity. New mutant glucose isomerases with an altered substrate specificity are provided according to this method. These altered properties are useful in starch degradation and in other sugar conversion reactions.

Glucose isomerases having altered substrate specificity

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Heverlee, Belgium

Anne-Marie Lambeir