Bacteria can carry out gluconeogenesis using components of the citric acid cycle or amino acids, but...

Bacteria can carry out gluconeogenesis using components of the citric acid cycle or amino acids, but unlike mammals, they can generate glucose from acetate via the glyoxylate pathway. Because bacteria have no organelles, the enzymes of the citric acid cycle and the glyoxylate pathway are not compartmentalized. (a) Why is regulation of the glyoxylate pathway necessary in bacteria? (b) Studies show that bacterial isocitrate lyase is allosterically inhibited by high concentrations of phosphoenolpyruvate. Would you expect to see the inhibition of isocitrate lyase when bacteria are utilizing glucose as a sole carbon source? Why? (c) Would you expect the glyoxylate pathway to be more active than the citric acid cycle when bacteria are growing on acetate? Why? (d) Would you expect to find glucose-6-phosphatase in bacteria?

Expert Solution

Vertebrates cannot convert the acetate to carbohydrates. Conversion of PEP to pyruvate and of pyruvate to acetyl coA are so exergonic as to be essentially irreversible. Moreover, vertebrates lack isocitrate lyase and malate synthase (glyoxylate cycle specific enzymes).

gladiator answered 4 months ago

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