title: Immobilization of beta-galactosidase on metal-chelate-substituted gels.
abstract: The use of copper, zinc, iron, nickel and calcium in three different chelating gels was investigated for preparing immobilized beta-galactosidase. The chelated ligands [Cu(2+)-iminodiacetate (IDA), Cu(2+)-Tris(carboxymethyl)ethylenediamine (TED), Ni(2+)-IDA and Fe(3+)-IDA] absorbed the protein so strongly that it can be considered a true immobilization. The obtained enzyme derivatives were investigated with regard to activity and stability. Enzymic activity was highly preserved in general for the TED derivates (90% when compared with that for Cu(2+)-TED). The immobilized Ni2+ derivatives were more stable to high temperature and to storage than the Cu2+ derivatives. Temperature-stability of the immobilized enzyme was very much improved by adding a strong metal-chelating gel such as carboxymethylated tetraethylenepentamine-agarose. The gel could be re-used and reloaded after elution with chelator. beta-Galactosidase from Escherichia coli was purified using immobilized-metal-ion-chelate chromatography (i.m.a.c.). The potential use of beta-galactosidase immobilized on i.m.a.c. gels for technical purposes is discussed.
authors.affiliation: Biochemical Separation Centre, Uppsala University, Uppsala Biomedical Center, Sweden.
authors.forename: B M
authors.initials: BM
authors.lastname: Brena
authors.forename: L G
authors.initials: LG
authors.lastname: Rydén
authors.forename: J
authors.initials: J
authors.lastname: Porath
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D002845:Chromatography; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D004926:Escherichia coli / Q000201:enzymology*; D005782:Gels / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D013696:Temperature; D001616:beta-Galactosidase / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002614:Chelating Agents; D004800:Enzymes, Immobilized; D005782:Gels; D001616:beta-Galactosidase