Enzyme responsive polymers response

To clarify the scope and the limitations of this approach, it was first of all necessary to ascertain whether precursors having modified monosaccharide residues may be accepted as substrates by the enzymes responsible both for assembly of the oligosaccharide repeating-units of the polymers and for their polymerization. 

In summary, the steady state and transient performance of the poly(acrylamide) hydrogel with immobilized glucose oxidase and phenol red dye (pAAm/GO/PR) demonstrates phenomena common to all polymer-based sensors and drag delivery systems. The role of the polymer in these systems is to act as a barrier to control the transport of substrates/products and this in turn controls the ultimate signal and the response time. For systems which rely upon the reaction of a substrate for example via an immobilized enzyme, the polymer controls the relative importance of the rate of substrate/analyte delivery and the rate of the reaction. In membrane systems, the thicker the polymer membrane the longer the response time due to substrate diffusion limitations as demonstrated with our pAAm/GO/PR system. However a membrane must not be so thin as to allow convective removal of the substrates before undergoing reaction, or removal of the products before detection. The steady state as well as the transient response of the pAAm/GO/ PR system was used to demonstrate these considerations with the more complicated case in which two substrates are required for the reaction. 

Many fruit and vegetable juices darken in color with time due to enzymic browning. The phenolic compounds involved in the reaction complex with cyclodextrin. Thus, the browning reaction can be prevented, either by passing the juice through a crosslinked cyclodextrin polymer to remove the phenol, or by adding cyclodextrin to the juice, since polyphenoloxidase, the enzyme responsible for oxidizing the phenolic compounds, is unable to act on the phenolic compounds while they are complexed with the cyclodextrin.98,99... 

Hyaluronan (hyaluronic acid, HA) is a highly anionic unbranched linear polymer containing a -GlcAfSl,4GlcNAcP 1,4-repeating unit, which plays important roles in modulating cell adhesion, signaling, and motility. Several enzymes responsible for HA synthesis, namely Hyaluronic Acid Synthases, have been cloned from bacteria and mammals (107, 108). 

Acrylamide is the first bulk chemical manufactured using an industrial biotransformation. Acrylamide which is produced 200000 t/a is an important industrial chemical that is mainly processed into water-soluble polymers and copolymers, which find applications as flocculants, paper-making aids, thickening agents, surface coatings, and additives for enhanced oil recovery. The chemical manufacture of acrylamide has been established for a long time, it is based on Cu-catalysis. The production of acrylamide using immobilized whole cells of Rhodococcus rhodochrous is a remarkable example of a lyase-catalyzed commercial process. The enzyme responsible for water addition to the double bond of acrylonitrile is nitrile hydratase (Eq. 4-17) ... 

Thornton, P.D. McConnell, G. Ulijn, R.V. Enzyme responsive polymer hydrogel beads. Chem. Commun. 2005, 47 (47), 5913-5915. 

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