Interplay of organic and biological chemistry in understanding coenzyme mechanisms: example of thiamin diphosphate-dependent decarboxylations of 2-oxo acids.
With the publication of the three-dimensional structures of several thiamin diphosphate-dependent enzymes, the chemical mechanism of their non-oxidative and oxidative decarboxylation reactions is better understood. Chemical models for these reactions serve a useful purpose to help evaluate the additional catalytic rate acceleration provided by the protein component. The ability to generate, and spectroscopically observe, the two key zwitterionic intermediates invoked in such reactions allowed progress to be made in elucidating the rates and mechanisms of the elementary steps leading to and from these intermediates. The need remains to develop chemical models, which accurately reflect the enzyme-bound conformation of this coenzyme.
Jordan
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Department of Chemistry and the Program in Cellular and Molecular Biodynamics, Rutgers, State University, Newark, NJ, USA. frjordan@newark.rutgers.edu
D000094:Acetoin Dehydrogenase / Q000737:chemistry / Q000378:metabolism*; D000105:Acetyl Coenzyme A / Q000737:chemistry / Q000378:metabolism; D000588:Amines / Q000737:chemistry / Q000378:metabolism; D003067:Coenzymes / Q000737:chemistry* / Q000378:metabolism; D003653:Decarboxylation; D005415:Flavins / Q000378:metabolism*; D010084:Oxidation-Reduction; D011522:Protons; D011767:Pyruvate Decarboxylase / Q000737:chemistry / Q000378:metabolism; D011771:Pyruvate Oxidase / Q000737:chemistry / Q000378:metabolism; D013835:Thiamine Pyrophosphate / Q000737:chemistry / Q000378:metabolism*; D008063:Thioctic Acid / Q000378:metabolism*
D000588:Amines; D003067:Coenzymes; D005415:Flavins; D011522:Protons; D000105:Acetyl Coenzyme A; D008063:Thioctic Acid; D000094:Acetoin Dehydrogenase; D011771:Pyruvate Oxidase; D011767:Pyruvate Decarboxylase; D013835:Thiamine Pyrophosphate