Problem 1
A one-way link. What reaction serves to link glycolysis and the citric acid cycle, and what is the enzyme that catalyzes the reaction?
Problem 2
Naming names. What are the five enzymes (including regulatory enzymes) that constitute the pyruvate dehydrogenase complex? Which reactions do they catalyze?
Problem 4
The ol' two step plus one. The conversion of pyruvate into acetyl CoA consists of three steps. What are these steps?
Problem 5
Predetermined events. The conversion of pyruvate into acetyl CoA commits the carbon atoms to either of two principal fates. What are the fates?
Problem 6
Coenzymes. What coenzymes are required by the pyruvate dehydrogenase complex, and what are their roles?
Problem 7
More coenzymes. Distinguish between catalytic coenzymes and stoichiometric coenzymes in the pyruvate dehydrogenase complex.
Problem 9
Like Watson and Holmes. Match each term with its description. (a) Acetyl CoA (b) Citric acid cycle (c) Pyruvate dehydrogenase complex (d) Thiamine pyrophosphate (e) Lipoic acid (f) Pyruvate dehydrogenase (g) Acetyllipoamide (h) Dihydrolipoyl transacetylase (i) Dihydrolipoyl dehydrogenase (j) Beriberi 1\. Catalyzes the link between glycolysis and the citric acid cycle 2\. Coenzyme required by transacetylase 3\. Final product of pyruvate dehydrogenase 4\. Catalyzes the formation of acetyl CoA 5\. Regenerates active transacetylase 6\. Fuel for the citric acid cycle 7\. Coenzyme required by pyruvate dehydrogenase 8\. Catalyzes the oxidative decarboxylation of pyruvate 9\. Due to a deficiency of thiamine
Problem 10
Alternative fates. Compare the regulation of the pyruvate dehydrogenase complex in muscle and in liver.
Problem 12
Flaking paint, green wallpaper. Claire Boothe Luce, ambassador to Italy in the \(1950 \mathrm{s}\) (and Connecticut congressperson, playwright, editor of Vanity Fair, and the wife of Henry Luce, founder of Time magazine and Sports Illustrated), became ill when she was staying at the ambassadorial residence in Rome. The arsenic-based paint on the dining-room ceiling was flaking; the wallpaper of her bedroom in the ambassadorial residence was colored a mellow green owing to the presence of cupric arsenite in the pigment. Suggest a possible cause of Ambassador Luce's illness.
Problem 13
Energy rich. What are the thioesters in the reaction catalyzed by PDH complex?
