Macrocyclic Enzyme Model System. Kinetic Activity of Paracyclophane Bearing 1,4-Dihydronicotinamide and 2-Pyridinecarboxylic Acid Moieties as Effected by Zinc Ion

Article abstract of DOI:10.1246/bcsj.55.2898

As regards the effect of zinc(II) ion on the reduction of hexachloroacetone, the kinetic activity of a <20>paracyclophane (PCP) bearing 1,4-dihydronicotinamide (HNA) and 2-pyridinecarboxylic acid (Py) moieties, HNA-PCP-Py, has been investigated as an alcohol dehydrogenase model in reference to that of PCP-HNA in the light of their metal-coordination behavior.The reduction ability of PCP-HNA was significantly lowered as it underwent complex formation with zinc.On the other hand, HNA-PCP-Py showed an apparent rate maximum in a relatively lower concentration range of ZnCl2.The kinetic behavior was analyzed on the basis of the formation of two kinds of zinc complexes of HNA-PCP-Py: the 1:1 complex , in which both Py and HNA moieties are simultaneously coordinated to the same zinc ion, showed a decreased reactivity relative to metal-free HNA-PCP-Py; while the 2:1 complex (HNA-PCP-Py-Zn^II-Py-PCP-HNA), in which HNA is free from metal-coordination, exercised a much enhanced activity, 7 times as reactive as metal-free HNA-PCP-Py.A plausible reaction mechanism for the enhanced reactivity has been discussed.

Full text of DOI:10.1246/bcsj.55.2898

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Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.