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Biology LibreTexts

B. Oxidative Enzymes

Skills to Develop

  • state the type of oxidizing reagent used and the products forms on oxidation reactions catalyzed by dehydrogenases, monoxygenases (hydroxylases), dioxygenases, and oxidases;
  • draw the reactive end of NAD+ and mechanisms showing it's reactions with substrates in enzyme-catalyzed two electron oxidation reactions;
  • explain differences in chemical reactivity of NAD+ and FAD in one and two electrons oxidations and with dioxygen;
  • describe the stereochemistry of the alcohol dehydrogenase-catalyzed oxidation of prochiral ethanol by NAD+;
  • explain why FAD/FADH2 are often tightly bound to dehydrogenases in contrast to NAD+/NADH where are freely diffusable substrates;
  • given standard reduction potentials, determine the ΔGo' for given redox reactions;
  • explain why different FAD and other flavin containing dehydrogenases have varying standard reduction potentials for the flavin but NAD+ dependent dehydrogenase have only one;
  • describe the role of heme in mono- and dioxygenases in activating dioxygen and minimizing side reactions of ROSs;
  • describe the biological role of cytochrome P450s;
  • define and give examples of oxidases;
  • compare the contrast the role of the heme in carrying hemoglobin and myoglobin, monoxygenases, and in oxidases.