Effects of Molecular Weight and Polymer Composition on Coupling Reactions of Lipase and Polyacrylic Acid or Acrylic Acid/Acrylamide Copolymers

Abstract

Coupling reactions of lipase with polyacrylic acid or acrylic acid/acrylamide copolymers were carried out using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a coupling reagent. The reaction temperature, pH, the molecular weight and concentration of polyacrylic acid had considerable effects on the coupling reactions. When the coupling reaction was carried out at 10°C and pH 7, the lipase content in the polymer-coupled lipase was slightly less and the relative activity of the coupled lipase was higher than those coupled at 20°C and pH 4. The lipase content in the polymer-coupled lipase decreased and the relative activity of the sample increased with the increase of molecular weight and decrease of polymer concentration. Acrylic acid/acrylamide copolymers with different composition were also used for the coupling reaction. The less acrylic acid component the copolymer had, the higher activity the coupled lipase showed. All results were explained in terms of the number of reaction sites defined as the number of polymer molecules per lipase molecule.