試題詳解

43. In the citric acid cycle, succinate is dehydrogenated by succinate dehydrogenase, which yields fumarate. The dehydrogenation of two of the four hydrogens in succinate (labeled as H₁~H₄ in the figure shown below) is stereospecific, with the pro-S hydrogen removed from one carbon atom and the pro-R hydrogen removed from the other.
  Which of the following two hydrogens could be abstracted in the four hydrogens of the succinate molecule in the reaction catalyzed by succinate dehydrogenase? a. H₁ and H₂ b. H₁ and H₃ c. H₁ and H₄ d. H₂ and H₃ e. H₂ and H₄ f. H₃ and H₄
(A) b and e
(B) c and d
(C) a and f
(D) Only c could occur.
(E) Only d could occur.