Modulation of Substrate Preference of Thermus Maltogenic Amylase by Mutation of the Residues at the Interface of a Dimer.

The article examines the relationship between the substrate size and geometric shape of the catalytic site of Thermus maltogenic amylase by substituting Gly50, Asp109, and Val431, located at the interface of the dimer, with bulky amino acids. Results indicate that the substituted bulky amino acid residues modified the shape of the catalytic site, such that the ability of the enzyme to differentiate between small and large molecules like amylose and amylopectin was improved.