Use of dextrans as long and hydrophilic spacer arms to improve the performance of immobilized proteins acting on macromolecules

Abstract

New dextran–agarose supports, suitable for covalent immobilization of enzymes and proteins acting on macromolecular substrates, were prepared. The thick internal fibers of agarose gels were covered by a low‐density layer of long, flexible, hydrophilic, and inert dextran molecules. Rennin and protein A were immobilized on these novel supports and the resulting derivatives exhibited a very high capacity for biological recognition of soluble macromolecular substrates. Caseinolytic activity of this immobilized enzyme was 15‐fold higher than activity of directly immobilized rennin, through short spacer arms, on agarose gels. Similarly, the new derivatives of immobilized protein A were able to adsorb up to 2 molecules of immunoglobulin per each molecule of immobilized protein A. When the immobilized proteins were secluded away from the support surface by using these new long and hydrophilic spacer arms, they exhibit minimal steric hindrances that could be promoted by the proximity of the support surface. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 518–523, 1998.

Lipase immobilization on epoxy-activated poly(vinyl acetate-acrylamide) microspheres

“…That is, an over-long incubation time led to the decline in activity recovery instead although the amount of lipase immobilized on microspheres increased. These results could be ascribed to lipase overloading that could cause molecular crowding and exert a steric hindrance effect, which agreed well with several recent reports [20,26]. Besides, a long incubation time would also cause partial inactivation of enzyme.…”

Sensitive Chemiluminescence Detection of Prion Protein on a Membrane by Using a Peroxidase-Labeled Dextran Probe

“…12300) was first activated by the oxidation of diols in the macromolecule with sodium periodate. 16 Dextran is a water-soluble macromolecule, and thus a synthetic reaction can be achieved in water. However, a water-insoluble gummy material was formed when all glucose units were oxidized.…”

Immobilization of enzymes on heterofunctional epoxy supports

“…), the orientation of the immobilized enzyme regarding the support is a key point: only if the active center is exposed to the medium, the protein will be able to recognize these large substrates [33][34][35][36] . In these cases, the use of different supports immobilizing the protein via different regions may yield at least one immobilized protein preparation having the biological activity.…”