title: Ion exchange immobilization of changed beta-galactosidase fusions for lactose hydrolysis.
abstract: The use of charged peptides fused to enzymes for immobilization onto ion-exchange membranes was explored for the enzyme x-galactosidase. The additional charged peptides, containing 1, 5, 11, and 16 aspartates, fused to x-galactosidase, for the most part did not interfere with the kinetic behavior for lactose hydrolysis. There was a 2-fold decline in V(m) for the 16-aspartate fusion, but the others were quite similar to the wild type enzyme (BGWT). BGWT and the fusions all retained approximately 50% of their activities when adsorbed onto ion-exchange membranes. In contrast to BGWT, the enhanced binding strength of the 11 aspartate fusion provided the ability to hydrolyze whey permeate at 0.3 M ionic strength without enzyme leakage, and to immobilize the enzyme directly from diluted cell extract with 83% purity.
authors.affiliation: Department of Chemical Engineering, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Heng
authors.forename: C E
authors.initials: CE
authors.lastname: Glatz