Enzymes temporarily immobilized

When enzymes are added to a mixture of two incompatible aqueous polymer solutions, they often partition to one of the phases (96, 97). Mixing produces a fine emulsion with droplets of one of the phases distributed in the other continuous phase. The enzyme that partitions into a droplet may be regarded as being temporarily immobilized (98). Mass transfer across the droplet interface is facilitated compared to traditional immobilized systems. Such systems are... 

Aqueous two-phase systems offer a unique possibility to operate with temporarily immobilized enzymes without sterical hindrances, as is often the case with traditionally immobilized preparations. The use of dye-modified macromolecules as substrates for monitoring enzymes degrading macromolecules has been proven successful. 

Polymeric or proteinaceous microspheres are used to introduce drugs to specific locations in the body. The coating material acts as a semipermeable membrane, permitting slow release and high concentration of a drug at the desired site. Enzymes, hormones, and other biochemical substances can be temporarily immobilized by this technique. 

Experiments with membranes containing immobilized proteins are more difficult than those in which the proteins are free and dissolved in the solution, later adsorbing temporarily to collect or give electrons to the promoter-modified electrode. In biological cells of living systems, the membranes, some with enzyme layers attached, are extremely thin. It would be difficult to find an experimental arrangement in which such a layer of actual biomaterial could be made into an electrode attached to an outer power source, etc. Because of such difficulties, the examination of electron transfer at the interfaces of biosystems has been a path less traveled. 

Finally, any enzymatic process using lipases or phospholipases can be triggered at will by changing the internal balance between the core water and the free water. On the shelf, the product will contain enzymes that will be immobilized and temporarily deactivated by the bound water, and when the microemulsion is further diluted, during use, the enzymes will become free and active and the reaction will be triggered. 

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