Evidence for a Mechanism Involving Transient Fragmentation in Carbon Skeleton Rearrangements Dependent on Coenzyme B12


  • This research was supported by the Commission of European Communities, the Deutsche Forschungsgemeinschaft, and the Fonds der Chemischen Industrie.

  • Dedicated to Professor Albert Eschenmoser on the occasion of his 70th birthday


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Enzyme kinetics and EPR spectroscopy provide evidence that in the reversible rearrangement of (S)-glutamate (1) to (2S, 3S)-3-methylaspartate (2), which is catalyzed by the coenzyme B12 dependent glutamate mutase from Clostridium cochlearium, the substrate 1 fragments into acrylate (3) and glycine radical (4), which recombine to 2. Ado-CH2-Cbl [DOUBLE BOND] 5′-adenosylcobalamin (coenzyme B12).