The thiamine-dependent enzyme （1R, 2S, 5S, 6S）-2-succinyl-5-enolpyruvyl-6-hydroxyl-3-cyclohexene-l-carboxylate （SEPHCHC） synthase, also known as MenD, catalyzes a Stetter-like reaction in the biosynthesis of vitam...The thiamine-dependent enzyme （1R, 2S, 5S, 6S）-2-succinyl-5-enolpyruvyl-6-hydroxyl-3-cyclohexene-l-carboxylate （SEPHCHC） synthase, also known as MenD, catalyzes a Stetter-like reaction in the biosynthesis of vitamin K. It is found to catalyze a novel reductive C-N bond ligation reaction between nitroarenes and et-ketoacids to form N-hydroxamates. This reaction likely pro- ceeds through an enzyme-mediated, slow two-electron reduction of the nitroalkanes to form a nitroso intermediate, which serves as the electrophilic acceptor of the ketoacid-derived acyl anion. The involvement of the nitroso intermediate is support- ed by the fact that similar N-hydroxamates are readily formed at a much higher rate when nitroso compounds replace the nitro substrates in the chemoenzymatic reactions. These results demonstrate that the thiamine-dependent enzyme is able to catalyze novel, nonnative reactions that may find new chemoenzymatic applications.展开更多
文摘The thiamine-dependent enzyme （1R, 2S, 5S, 6S）-2-succinyl-5-enolpyruvyl-6-hydroxyl-3-cyclohexene-l-carboxylate （SEPHCHC） synthase, also known as MenD, catalyzes a Stetter-like reaction in the biosynthesis of vitamin K. It is found to catalyze a novel reductive C-N bond ligation reaction between nitroarenes and et-ketoacids to form N-hydroxamates. This reaction likely pro- ceeds through an enzyme-mediated, slow two-electron reduction of the nitroalkanes to form a nitroso intermediate, which serves as the electrophilic acceptor of the ketoacid-derived acyl anion. The involvement of the nitroso intermediate is support- ed by the fact that similar N-hydroxamates are readily formed at a much higher rate when nitroso compounds replace the nitro substrates in the chemoenzymatic reactions. These results demonstrate that the thiamine-dependent enzyme is able to catalyze novel, nonnative reactions that may find new chemoenzymatic applications.
