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Biochemistry 18

A 42-year-old man presents to the physician accompanied by his wife with concern about short-term memory for the past 2 weeks. The wife says that he tends to make up stories rather than telling her the truth. He underwent gastric bypass surgery 3 months ago. Vital signs are within normal limits. Physical examination shows symmetric peripheral neuropathy in the lower extremities with motor and sensory changes. He is diagnosed with a vitamin deficiency.

Which of the following enzymes in the Krebs cycle requires this vitamin to work?

  • A) α-ketoglutarate dehydrogenase
  • B) Citrate Synthase
  • C) Methionine synthase
  • D) Pyruvate dehydrogenase
  • E) Succinylcholine CoA synthase


Husban Hamil


Dr. Ted O'Connell