Gluconeogenesis: Hydrolysis Reactions Flashcards
True or false: All of the reactions from PEP to FBP are freely reversible.
True
What enzyme catalyzes the conversion of FBP to F6P?
Fructose 1, 6-bisphosphatase (FBPase)
What type of reaction does FBPase catalyze?
A hydrolysis reaction of FBP to F6P
What enzyme catalyzes the conversion of G6P to glucose?
Glucose-6-phosphatase (G6Pase)
True or false: The enzyme that converts G6P to glucose is the also the enzyme used to convert glycogen to G6P.
True (glucose-6-phosphatase)
In what organs is the enzyme that converts G6P to glucose present?
Liver and kidneys
What kind of reaction is the conversion of G6P to glucose by G6Pase?
Hydrolysis reaction
True or false: FBPase and G6Pase convert ATP to ADP in their hydrolysis reactions.
False; they release inorganic phosphate (Pi)
What is the net energetic cost of converting 2 pyruvate to 1 glucose by gluconeogenesis?
6 ATP equivalents (2 in pyruvate carboxylase, 2 in PEP carboxykinase, and 2 in phosphoglycerate kinase)
What is the net ATP production of glycolysis?
2 ATP
What is the net cost of gluconeogenesis?
6 ATP equivalents
What is the net loss of cycling glucose to pyruvate then back to glucose?
4 ATP equivalents
What is the endpoint of gluconeogenesis?
Glucose
In what ways can the intermediates in gluconeogenesis be diverted from going to glucose?
1) Can be directed to the Pentose Phosphate Pathway for R5P production.
2) G6P can be converted to G1P for glycogen.
Where does gluconeogenesis end in most tissues besides the liver?
At Glucose-6-phosphate, which is then converted to glycogen.
