Improved Hydrolysis of Granular Starches by a Psychrophilic α-Amylase Starch Binding Domain-Fusion
Research output: Contribution to journal › Journal article › Research › peer-review
Degradation of starch granules by a psychrophilic α-amylase, AHA, from the Antarctic bacterium Pseudoalteromonas haloplanktis TAB23 was facilitated by C-terminal fusion to a starch-binding domain (SBD) from either Aspergillus niger glucoamylase (SBDGA) or Arabidopsis thaliana glucan, water dikinase 3 (SBDGWD3) via a decapeptide linker. Depending on the waxy, normal or high-amylose starch type and the botanical source, the AHA-SBD fusion enzymes showed up to 3 times higher activity than AHA wild-type. The SBD-fusion thus increased the density of enzyme attack-sites and binding-sites on the starch granules by up to 5- and 7-fold, respectively, as measured using an interfacial catalysis approach that combined conventional Michaelis-Menten kinetics, with the substrate in excess, and inverse kinetics, having enzyme in excess, with enzyme-starch granule adsorption isotherms. Higher substrate affinity of the SBDGA compared to SBDGWD3 was accompanied by the superior activity of AHA-SBDGA in agreement with the Sabatier principle of adsorption limited heterogenous catalysis.
Original language | English |
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Journal | Journal of Agricultural and Food Chemistry |
Volume | 71 |
Issue number | 23 |
Pages (from-to) | 9040-9050 |
Number of pages | 11 |
ISSN | 0021-8561 |
DOIs | |
Publication status | Published - 2023 |
- alpha-Amylases/chemistry, Hydrolysis, Protein Structure, Tertiary, Starch/chemistry, Amylose/chemistry
Research areas
ID: 358498322