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Synthetic enzyme

There are at least three reasons for attempting to prepare solid-phase catalysts that resemble enzymes. Synthetic procedures would generally be simplified. Catalytic groups are fixed on the support so that they cannot interact with one another, for example, thiols cannot deactivate by forming disulfides and metal ions cannot deactivate by forming binuclear structures. Finally, if the successful catalyst is eventually made, it will almost certainly be used in heterogeneous systems. [Pg.220]

Inspired by the efficiency and selectivity of Nature, synthetic chemists have admired the ability of enzymes to activate otherwise unreactive molecules in the confines of an active site. Although much less complex than the evolved active sites of enzymes, synthetic host molecules have been developed that can carry out complex reactions within their cavities. While progress has been made towards highly efficient and selective reactivity inside synthetic hosts, the lofty goal of duplicating enzymes specificity remains [7-9]. Pioneered by Lehn, Cram, Pedersen, and Breslow, supramolecular chemistry has evolved well beyond the crown ethers and cryptands originally studied [10-12]. Despite the increased complexity of synthetic host molecules, most assembly conditions utilize self-assembly to form complex highly-symmetric... [Pg.165]

N—O-sulfation of minoxidil in the presence of adenosine-3 -phospho-5 -phosphosulfate (PAPS) (equation 24). The enzyme-synthetized product was identical to authentic N—O-sulfate with respect to chromatographic behavior and mass spectral characteristics and was split to minoxidil when treated with sulfatase183. The pH optimum for minoxidil N—O-sulfation was about 8.0. Enzyme activity in crude preparations was maintained for several months during storage at —76°C, while activity of partially purified enzyme was lost under these conditions183. [Pg.1655]

In the example of the asymmetric epoxidation of olefins, enzymes, synthetic catalysts, and catalytic antibodies have been compared side-by-side with respect to performance in chemical synthesis (Jacobsen, 1994). Epoxidation of olefins is a reaction of considerable industrial interest where, historically, enzymes have not performed extremely well. One reason is the dependence of the enantiomeric purity of the diol and epoxide products on the regiospecificity of the attack on the racemic epoxide by a water molecule (Figure 20.1). [Pg.570]

Other Disaccharides. Amino sugar-containing di- and oligo-saccharides of undetermined structure have been demonstrated in certain enzymic, synthetic reactions.298... [Pg.277]

A number of enzymes appear therefore to be localized in a specific micro-environment, which can influence. their biocatalytic activity. Because of the complexity of biological membranes, our understanding of the influence of micro-environmental effects on membrane-bound enzyme is minimal. An important contribution to better understanding the mode of action of membrane-bound enzyme has been the development of the concept of heterogeneous catalysis by enzymes synthetically bound to water-insoluble supports. These immobilized enzymes were viewed as models for the cellular bound enzyme (3,A). [Pg.207]

HA synthase from Streptococcus equisimilis was employed for milligram-scale synthesis of HA (109). In this reaction system, UDP-sugars (UDP-GlcA and UDP-GlcNAc) were effectively regenerated by the catalyses of several enzymes, synthetic HA was produced in 90% yield. In addition, mutated HA synthase from Type A Pasteurella multocida (PmHAS 1-703 aa) was recently used for the stepwise synthesis of HA, which has a monodispersed molecular mass of up to 20 sugar units (110). [Pg.410]

Zhao, M. Song, D. Lippard, S. J. Water induces a structural conversion and accelerates the oxygenation of carboxylate-bridged non-heme diiron enzyme synthetic analogues. Inorg. Chem. 2006, 45, 6323-6330. [Pg.185]

Mode of Action of the Enzyme. Synthetic substrate, Z-Gly-Pro-Leu-Gly, was incubated with this purified enzyme at 30°C, pH 3.1. Measurements of the released amino acids were made with an amino acids analyzer (Hitachi, Model L-8500) throughout the time of incubation. From the reaction of the enzyme on the substrate, Gly at the C-terminus was first released. Next released was Leu, which is in the penultimate position. From the sequential release of amino acids from the C-terminus, it was confirmed that the enzyme is a carboxypeptidase, which was named CPase Top. [Pg.168]

Ized such as carbohydrates, nucleic acids, lipids, and proteins may prove available by enzymic synthetic methods. Enzymology will be useful in modifications of poly- and oligosaccharides and proteins. Enzymes will also see growth in applications in medical diagnostics and treat-... [Pg.270]

Amperometric biosensors are generally composed of conventional metal electrodes and mediators that can shuttle electrons from the electrode to the active centre commonly buried deep within the polypeptide structure of the enzyme. Synthetic metals, including poly aniline, have also attracted considerable attention as electrochemical transducers for a variety of enzyme-based sensor devices. Significantly, these electrodes facilitate electron transfer to an enzyme without an added mediator species. This approach has simplified the construction of biosensors and also obviates sluggish kinetics, which are deleterious to precise detection (Figure 12.27)... [Pg.557]

The concept of TSAS was further proven to be vahd by the following experiments. Chi-oxa monomer was subjected to polymerization by enzymatic catalysis. The hydrolysis enzymes used were chitinase (family 18) involving an oxazohnium intermediate and lysozyme involving an oxocarbenium ion intermediate (Fig. 13). With the former enzyme, synthetic chitin was quantitatively obtained after 50 h at pH 10.6, whereas with the latter no chitin was produced after 165 h of reaction [69]. This imphes that the oxazoline monomer could not be a substrate for the lysozyme enzyme. [Pg.188]


See other pages where Synthetic enzyme is mentioned: [Pg.286]    [Pg.327]    [Pg.58]    [Pg.181]    [Pg.40]    [Pg.54]    [Pg.933]    [Pg.163]    [Pg.182]    [Pg.191]    [Pg.932]    [Pg.54]    [Pg.54]    [Pg.269]    [Pg.146]    [Pg.231]    [Pg.62]    [Pg.62]    [Pg.124]    [Pg.414]    [Pg.224]    [Pg.111]   
See also in sourсe #XX -- [ Pg.437 ]




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