Catalysis of dehydrogenation of 4-trans-(N,N-dimethylamino)cinnamaldehyde by aldehyde dehydrogenase
| Autor: | Marek Dryjanski, Wojciech Ambroziak, Darryl P. Abriola, Regina Pietruszko, Teresa Lehmann |
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| Rok vydání: | 2001 |
| Předmět: |
Stereochemistry
Aldehyde dehydrogenase In Vitro Techniques Toxicology Binding Competitive Medicinal chemistry Catalysis Cinnamaldehyde Cofactor chemistry.chemical_compound Catalytic Domain Animals Humans Magnesium Dehydrogenation Chloral Hydrate Fluorescent Dyes chemistry.chemical_classification Aldehydes biology General Medicine Aldehyde Dehydrogenase Hydrogen-Ion Concentration Dissociation constant Kinetics Spectrometry Fluorescence Enzyme chemistry Cinnamates biology.protein Stoichiometry |
| Zdroj: | Chemico-Biological Interactions. :103-114 |
| ISSN: | 0009-2797 |
| DOI: | 10.1016/s0009-2797(00)00226-x |
| Popis: | 4-trans-(N,N-dimethylamino)cinnamaldehyde (DACA) is a chromophoric and fluorogenic substrate of aldehyde dehydrogenase. Fluorescence of DACA is enhanced by binding to aldehyde dehydrogenase in the absence of catalysis both in the presence and absence of the coenzyme analogue 5'AMP. DACA binds to aldehyde dehydrogenase with a dissociation constant of 1-3 microM and stoichiometry of 2 mol mol(-1) enzyme. Incorporation of DACA during catalysis was also investigated and found to be 2 mol DACA mol(-1) enzyme. Effect of pH on the stoichiometry of DACA incorporation during catalysis has shown that DACA incorporation remained constant at 2 mol DACA mol(-1) enzyme, despite a 74-fold velocity enhancement between pH 5.0 and 9.0. Increase of pH increased decomposition of enzyme-acyl intermediate without affecting the rate-limiting step of the reaction. At pH 7.0 the pH stimulated velocity enhancement was 10-fold over that at pH 5.0; further velocity enhancement (11.5-fold that of pH 7.0) was achieved by 150 microM Mg(2+) ions. The velocity at pH 7.0 with Mg(2+) exceeded that of pH 9.0, and that at maximal pH stimulation at pH 9.5. It was observed that level of intermediate decreased to about 1 mol mol(-1) enzyme, indicating that Mg(2+) ions increased the rate of decomposition of the enzyme-acyl intermediate and shifted the rate-limiting step of the reaction to another step in the reaction sequence. |
| Databáze: | OpenAIRE |
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