Enzyme model systems

Homochiral molecules readily available from inexpensive sources are useful synthetic building blocks and chiral auxiliaries. 1,4-01-0-benzyl-L-threitol has been used in construction of homochiral crown ethers that are useful as enzyme model systems. Topologically controlled diastereoselective delivery of the Simmons-Smith reagent for 2-cycloalken-l-one 1,4-d1-0-benzyl-L-threitol ketals was recently reported. ... 

Carbonyl dehydrogenase enzymes, model systems, 8, 4 Carbonyl derivatives, a-arylation, 1, 361 Carbonyl-ene reactions... 

Monomeric Metaphosphates in Enzymic and in Enzyme-Model Systems... 

The model systems for enzymes activated by light can be called artificial photoenzymes . This expression comprises two important requirements, which must be fulfilled by system its activity should be triggered by light and it should behave like an artificial enzyme . The term artificial enzyme is very often used inappropriately and applied to any catalysts. The detailed explanation of this term, together with critical analysis of enzyme model systems, can be found in an excellent review by Kirby [35], In general, enzymes are more than just highly developed catalysts ... 

Guldi DM, Rahman GMA, Jux N, Balbinot D, Hartnagel U, Tagmatarchis N, Prato M (2005) Functional single-wall carbon nanotube nanohybrids associating SWNTs with water-soluble enzyme model systems. J Am Chem Soc 127 9830-9838... 

Leussing and co-workers have studied other enzyme-model systems, such as the dimerization of pyruvate catalysed by Ni and Zn". The kinetics and mechanism of the hydrolysis of AT-salicylideneaniline in the presence of metal ions have also been reported, and Gansow and Holm... 

Several authors have invoked this general type of behaviour for metals in enzyme-model systems and it is likely that research in this area will increase in view of the desire to design model systems for the large group of metal enzymes in which geometrical effects involving the groups bound to the metal ion seem to be important. 

Active immobilized enzyme model system for investigation of the use of immobilized lysozyme as a bactericide in enzyme columns... 

The participation of reactive groups at the active site provides specificity not only for the substrates that will bind, but also for the reaction that will be catalysed. For example, in a non-enzymic model system, an amino acid may undergo (X-decarboxylation to yield an amine, transfer of the a-amino group and replacement with an oxo-group (section 9.3.1.2), isomerization between the d- and L-isomers, or a variety of reactions involving elimination or replacement of the side-chain. In an enzyme-catalysed reaction only one of the possible reactions will be catalysed by any given enzyme. 

A marcrocyclic enzyme model system has also been developed in recent years by Murakami s group in Japan (146,147). They found that 11-amino-[20] paracyclophan-lO-ol catalyzes the deacylation of p-nitrophenylhexa-decanoate with a rate 1000-fold greater that 2-aminocyclodecanol. 

Y. Murakami, Y. Aoyama, M. Kada, and J. L Kikuchi (1978), Macrocyclic enzyme model system Catalysis of ester degradation by a [20] paracyclophane bearing nucleophilic and metal-binding sites. Chem. Commun. 494-496. 

Sharif, S., Schagen, D., Toney, M.D., and Limbach, H.H. (2007) Coupling of functional hydrogen bonds in pyridoxal-5 -phosphate-enzyme model systems observed by solid state NMR... 

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