The insolubilisation of β-D-glucosidase by attachment to glass

Immobilization of glucoamylase on gelatin by transition-metal chelation

The potential applicability of glutaraldehyde-crosslinked-gelatin particles for the immobilization of enzymes by encapsulation has been extended by addition of surface-bound enzyme, leading ultimately to a method for the preparation of dual immobilized enzyme conjugates. Attachment of enzyme to the surface of the capsules was achieved by a transition-metal chelation process in which the incoming enzyme becomes a ligand. Glucoamylase was so immobilized, using titanium-urea, -acrylamide, -citric acid, and -lactose complexes or titanium (IV) chloride as means of introducing the titanium chelating centre. The retentions of enzyme activity for both the surface-bound and pre-encapsulated enzymes were functions of the chelating complex chosen. Differences were observed between the action patterns of the two forms of immobilized enzyme. These action patterns and the production of reversion products are discussed in the light of application of gelatin-immobilized glucoamylase to the production of high-DE glucose syrups.

The use of titanium (IV) oxide for the immobilisation of carbohydrate-directed enzymes

The use of particles of porous titanium (IV) oxide as a suitable matrix for enzyme immobilisation has been investigated with dextranase. Treatment of the particles with enzyme in the presence and absence of ammonium ions showed that the presence of ammonia induced a greater coupling of protein, whereas a greater retention of enzyme specific activity was achieved in the absence of ammonia. Properties of the immobilised enzyme include a pH-dependence and reversibility of the coupling between enzyme and matrix. The immobilised dextranase was most stable at pH 5.0. Automated analytical techniques for measuring the activity of dextranase and other polysaccharidases in soluble and insoluble forms are also reported.

Magnetic, immobilised derivatives of enzymes

A novel, water, insoluble, stable coating has been attached to various metals, which is capable of covalent attachment to enzymes. The coating (aminobenzoic acid-formaldehyde resin) can be attached to nickel, cobalt, tin, iron, and aluminium. beta-D-Glucosidase has been attached to the coated metals by diazotisation of the coating. The stability and usefulness of the resulting, metallic enzyme-preparations is discussed with special emphasis on the value of ferromagnetic supports for enzymes.