Summary and Bibliography of Chapter 3

1. Immobilisation of enzymes enables their efficient and continuous use. The rationale behind immobilisation is the easy separation of product from the biocatalyst.
2. Enzymes may be immobilised by adsorption, covalent binding, entrapment and membrane confinement, each method having its pros and cons. Adsorption is quick, simple and cheap but may be reversible. Covalent binding is permanent but expensive. Entrapment is generally applicable but may cause diffusional problems. Membrane confinement is a flexible method but expensive to set up.
3. Immobilisation of enzymes may have a considerable effect on their kinetics. This may be due to structural changes to the enzyme and the creation of a distinct microenvironment around the enzyme. The activity of an immobilised enzyme is governed by the physical conditions within this microenvironment not those prevalent in the bulk phase. The immobilisation matrix affects the partition of material between the product phase and the enzyme phase and imposes restrictions on the rate of diffusion of material.
4. Some effects of enzyme immobilisation are seen to be beneficial while others are detrimental to the economics of their use.

References and Bibliography

1. Bodálo, A., Gómez, J.L., Gómez, E., Bastida, J., Iborra, J.L. & Manjón, A. (1986). Analysis of diffusion effects on immobilized enzymes on porous supports with reversible Michaelis-Menten kinetics. Enzyme and Microbial Technology8, 433-8.
2. Engasser, J-M. & Coulet, P.R. (1977). Comparison of intrinsic stabilities of free and bound enzymes by graphical removal of diffusional effects. Biochimica et Biophysica Acta 485, 29-36.
3. Engasser, J-M. & Horvath, C. (1973). Effect of internal diffusion in heterogeneous enzyme systems: Evaluation of true kinetic parameters and substrate diffusivity. J. Theoretical Biology 42, 137-55.
4. Engasser, J-M. & Horvath, C. (1974). Buffer-facilitated proton transport pH profile of bound enzymes. Biochimica et Biophysica Acta 358 178-92.
5. Engasser, J-M. & Horvath, C. (1976). Diffusion and kinetics with immobilised enzymes. In Applied biochemistry and bioengineering, vol. 1 Immobilised enzyme principles. ed. L.B.Wingard, 
6. E.Katchalski-Katzir & L.Goldstein, pp 127-220, New York: Academic Press.European Federation of Biotechnology (1983). Guidelines for the characterization of immobilised biocatalysts. Enzyme and Microbial Technology  5, 304-7.
7. Goldstein, L. (1972). Microenvironmental effects on enzyme catalysis. A kinetic study of polyanionic and polycationic derivatives of chymotrypsin. Biochemistry, 11, 4072-84.
8. Israelachvili, J. & Pashley, R. (1982). The hydrophobic interaction is long range, decaying exponentially with distance. Nature, 300 341-2.
9. Kennedy, J.F. & Cabral, J.M.S., (1987). Enzyme immobilisation. In Biotechnology, vol. 7a, Enzyme Technology, ed. J.F.Kennedy, pp 347-404. Weinheim: VCH Verlagsgesellschaft mbH. 
10. Martinek, K., Klibanov, A.M., Goldmacher, V.S. & Berezin, I.V. (1977a). The principles of enzyme stabilization 1. Increase in thermostability of enzymes covalently bound to a complementary surface of a polymer support in a multipoint fashion. Biochimica et Biophysica Acta, 485, 1-12. 
11. Martinek, K., Klibanov, A.M., Goldmacher, V.S., Tchernysheva, A.V., Mozhaev, V.V., Berezin, I.V. & Glotov, B.O. (1977b). The principles of enzyme stabilization 2. Increase in the thermostability of enzymes as a result of multipoint noncovalent interaction with a polymeric support. Biochimica et Biophysica Acta 485, 13-28.
12. Woodward, J. (1985). Immobilised enzymes: Adsorption and covalent coupling. In Immobilised cells and enzymes A practical approach, ed. J.Woodward, pp 3-17. Oxford: IRL Press Ltd.
13. Working party on immobilised biocatalysts. (1983). Guidelines for the characterization of immobilised biocatalysts. Enzyme and Microbial Technology, 5, 304-307.