Enzyme analogs

Finally, chiral crown ethers have been utilized successfully both as enzyme mimics and as enzyme analogs. Important examples in the literature include... 

Wulff G, Akelah A. Enzyme-analog built pol3Tners. 6. Synthesis of 5-vinylsaUcylaldehyde and a simplified synthesis of some divinyl derivatives. Makromol Chem 1978 179 ... 

Wulff G, Grobe-Einsler R, Vesper W, Sarhan A. Enzyme-analog built polymers. 5. The specificity distribution of chiral cavities prepared in synthetic polymers. Makromol Chem... 

Wulff G, Sarhan A. Use of polymers with enzyme-analogous structures for the resolution of racemates. Angew Chem Int Ed Engl 1972 1 341. 

Wulff G, Schauhoff S. Enzyme-analog-built polymers. 27. Racemic-resolution of free sugars with macroporous polymers prepared by molecular imprinting—selectivity dependence on the arrangement of functional-groups versus spatial requirements. J Qrg Chem 1991 56 395-400. 

Ladd, J. N., and Butler, J. H. A. (1975). Humus-enzyme systems and synthetic, organic polymer-enzyme analogs. In Soil Biochemistry, Vol. 4, Paul, E. A., and McLaren, A. D., eds., Marcel Dekker, NewYork, 143-194. 

Polymeric enzymes and enzyme analogs constitute a completely separate topic. This field has recently been reviewed 133). Some of the materials described act as heterogeneous catalysts and could also be considered as polymeric heterogeneous catalysts. 

Lindsey, Alan S. Polymeric Enzymes and Enzyme Analogs. J. Makromol. Chem. C 3, 1 (1969). 

These results demonstrate that the side pocket of COX-1, which has been considered sterically inaccessible, can bind certain (5)-hydroxyethylamide derivatives of INDO. This study also offers insight into the selective binding of amide derivatives of INDO to COX-2. It seems that the amides associate with COX-1 and COX-2 but only bind tightly to COX-2. If all INDO-amides adopt a conformation in both enzymes analogous to that of the (i )-hydroxyethylamide 8, then this complex is only stable in COX-2. Because the orientation of Arg-120 is altered in the COX-1-compound 8 complex relative to other COX-1 inhibitor complexes, it may be that COX-2 can better accommodate this conformation than COX-1. It will be interesting to test this hypothesis and to identify the protein determinants responsible for the differential stability. 

Before discussing these graphic techniques it would be helpful to reiterate the reasons for using these enzyme analogies for heterogeneously catalyzed reactions. The most important of these is to incorporate into the kinetic analyses... 

Tris(pyrazolyl)methanesulfonates Enzyme-analog reactions [218 n]... 

Biocatalytic, enzyme-analogous, and antibody processes are under intensive investigation (cf. Section 3.2.1 see, for example, [17, 78, 82]). 

Since 1996, micellar catalysis (Section 3.1.11) has made progress in the same time as supercritical fluids (Section 3.1.13) have come to the fore. Suffice it to say that biocatalysis and enzyme-analogous processes enjoy an exponential growth that has significance both to basic science and to industry (Section 3.2.1). 

Because of its potential effects on 5a-reductase enzymes, analogous to finasteride, saw palmetto should not be used during pregnancy. 

Wulff, G. Vesper, W. Grobe-Einsler, R. Sarhan, A. Enzyme-analog built polymers, 4. The synthesis of polymers containing chiral cavities and their use for the resolution of racemates. Makro-mol. Chem. 1977, 178 (10), 2799-2816. 

Oxidation of L-arginine by a strain of Nocardia sp. produces nitric oxide and L-citrulline (Chen and Rosazza 1995). The enzyme (nitric oxide synthase) carries out two distinct reactions (1) hydroxylation of L-arginine catalyzed by an enzyme analogous to cytochrome P-450 and (2) a one-electron oxidation of Na -hydroxy-L-arginine to NO and L-citrulline. 

The incorporation of thiocyanate into the isocyanide axisonitrile-3 (20) may indicate that A. cavernosa is able to desulphurise thiocyanate. Some enzymes, such as glutathione S-transferases and some peroxidases, can convert thiocyanate to cyanide [82-85] marine sponges are known to contain peroxidases [43]. Alternatively conversion of the terpene isothiocyanate group to an terpene isocyanide by desulphurisation could occur using an enzyme analogous to the peroxidases, but programmed to use a secondary metabolite such as (21) as substrate. 

More recently, glycosomes have been described (3). These structures, reviewed in Chapter 2, provide a very different packaging for the glycolytic enzymes, but have not been exploited for purposes of chemotherapy. This may be because the compartmen-talization of these enzymes, which provides a very favorable biochemical environment for the capture of energy, still involves the same enzymes analogous to those found in mammalian cells. Inhibitors must be based on differences in the structures of these enzymes which differentiate them from their mammalian counterparts. This may not provide the necessary differences in specificity which are requisite for chemotherapy. 

The reaction to be catalyzed poses problems for the enzyme [34]. The abstraction of a proton from an aliphatic carbon atom is generally difficult and slow. The plf of the carbon-bound a-proton of mandelic acid is 22.0 [55], while the p/f the a-proton of the mandelate anion (as for the phenylacetate anion) is approximately 29 [36, 37]. In spite of this, mandelate racemase increases the rate of the racemiza-tion reaction by a factor of 1.7 x 10 to approximately 1000 per second at 25 °C at pH 7 [57, 55]. Interactions of mandelate with enzyme, analogous to those with inhibitor (5)-atrolactate in which one carboxylate oxygen atom is coordinated to the magnesium ion and also hydrogen-bonded to the e-ammonium group of Lysi 64,... 

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