L21: Gluconeogenesis Flashcards
glycogen reserves and daily glucose need
glycogen reserves hold 190g of glucose
daily need 160g
thus reserves can compensate for 1 day of fasting
where does gluconeogenesis occur?
liver and kidney
glucose synthesis is from non-____ precursors
non-carb
lactate, amino acids, glycerol
what are the 4 enzymes in gluconeogenesis that are not present in glycolysis?
pyruvate carboxylase
phosphoenolpyruvate carboxykinase
fructose 1,6-biphosphatase
glucose 6-phosphatase
Glucose-6-phosphatase
located in ER lumen
converts G6P to free glucose that can leave the cell
muscles do not have this enzyme thus glucose cannot leave the cell
what enzyme is not found in the cytosol?
pyruvate carboxylase
how is glucose 6 phosphatase moved around the cell?
lives in the ER lumen
T1 transports it to ER
T2 transports pi to cytosol
T3 transports glucose to cytosol
in gluconeogenesis, _______ is converted to glucose but first is converted into?
pyruvate
into oxaloacetate OAA
by pyruvate carboxylase
how is OAA transported to cytoplasm? why is this necessary?
malate shuttle
because the enzyme that converts pyruvate to OAA is found in the mitochondria
OAA is converted to _________ by ?
phosphoenolpyruvate
phosphoenolpyruvate carboxykinase
GTP used
phosphoenolpyruvate is converted to ? by ?
2-phosphoglycerate
enolase
2-phosphoglycerate is converted to ? by ?
3-pg
phosphoglycerate mutase
3-phosphoglycerate is converted to ? by ?
1,3-BPG
phosphoglycerate kinase
ATP used
1,3-biphosphoglycerate is converted to ? by?
GAP
GAP dehydrogenase
4 steps of converting GAP to glucose
- gap to fructose 1,6-bp by aldose
- F16BP to F6P by F16BPtase
- F6P to G6P by phosphoglucose isomerase
- G6P to free glucose by G6Ptase
