Conformational catalysis

The reactions of intramolecular cross-linking is a rather poorly investigated area in the field of macro-molecular reactions. However, the problems of regularities of such processes are related to such important problems of polymer chemistry as chemical modification of polymers, networks formation, sorption of low molecular reagents by polymers, intramolecular catalysis, conformational transitions and so on. In spite of the great importance of the study of regularities of cross-linking reactions, the experimental and theoretical analysis of such processes is complicated by many difficulties. ... 

Intramolecular Catalysis Multifunctional Catalysis Conformation and Strain Effects... 

It is a major challenge to elucidate the mechanisms responsible for the efficiencies of enzymes. Jencks (1) offered the following classification of the mechanisms by which enzymes achieve transition state stabilization and the resulting acceleration of the reactions proximity and orientation effects of reactants, covalent catalysis, general acid-base catalysis, conformational distortion of the reactants, and preorganization of the active sites for transition state complementarity. 

It seems from product distribution studies that even after dissociation of the MMOB from the diferrous MMOH, the active site in MMOH remembers that it had just been in complex with MMOB. This is presumably because MMOB induces a metastable (on the time scale of catalysis) conformation of the MMOH (129). The effect is observed as a hysteresis effect upon titration with MMOB to the diferrous MMOH (see Fig. 13 for a model), where a ratio 0.1 of MMOB/(MMOH active site) could induce a complete metastable conformation of MMOH. This could be observed by a drastic change in product distribution, and no further change in product distribution was observed in the presence of higher ratios of MMOB/MMOH. The model was corroborated by the low ratio of MMOB/MMOH needed to induce the MMOB-dependent changes of the diferrous MMOH EPR signal (129). The affinity between MMOB and MMOH depends on the redox state of MMOH. This explains... 

Pyridoxal 5 -Phosphate-Dependent Enzymes Catalysis, Conformation, and Genomics... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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