Biology 9700 · AS & A Level · Mode of action of enzymes

Mode of action of enzymes — practice question

Succinic dehydrogenase is an enzyme that catalyses the conversion of succinate into fumarate during aerobic respiration. Malonate is a reversible inhibitor of succinic dehydrogenase. By binding to the enzyme’s active site, malonate lowers the enzyme’s activity. Malonate and succinate are unable to bind to the active site at the same time. Which statement explains the effect of malonate on the activity of succinic dehydrogenase?

  • AIn the presence of malonate, Vmax can still be reached if the concentration of succinate is increased.
  • BMalonate has no effect on the Km.
  • CIn the presence of malonate, Vmax can still be reached if the concentration of fumarate is increased.
  • DMalonate decreases the Km.

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