Gluconeogenesis Flashcards
What are the three enzymes that need bypassing in gluconeogenesis?
Pyruvate kinase,
PFK-1
and Glucokinase
How is glucokinase bypassed in gluconeogenesis?
glucose 6- phosphatase
How is pyruvate kinase bypassed in gluconeogenesis?
Phosphoenolpyruvate Carboxykinase (PEPCK)
Pyruvate must be transformed to Acteyl-CoA first before going back to PEP (by pryuvate dehydrogenase rxn)
Acteyl-CoA goes to oxaloaceatate–>malate back to oxaloacetate–> phosphoenolpyruvate (PEP)
How is PFK-1 bypassed in gluconeogenesis?
F-1,6 bisphosphatase
Glucagon inhibits glycolysis by? (by decreasing ___ and by phosphorylating ____?)
decreasing fructose-2,6 bisphosphate
and phosphorylating PK (which deactivates PK)
With type two diabetes (aka insulin resistance), insulin fails to inhibit _____?
gluconeogenesis, results in excess blood glucose levels
alanine inhibits what enzyme during gluconeogenesis?
pyruvate kinase
what are enzymes of non hormonal regulators of hepatic gluconeogenesis?
glucose 6 phosphatase
fructose 1,6 bisphophatase
phosphoenolpyruvate carboxykinase (PEPCK)
pyruvate carboxylase
what is the non-hormonal regulator that is unique to gluconeogenesis? what does it activate?
acteyl-CoA, which activates pyruvate carboxylase
what is fructose 1,6 bisphosphatase inhibited by? (2 things)
AMP
And fructose 2,6 bisphosphate
the two pathways are _____ regulated in the liver to avoid a futile cycle.
reciprocally
what else can become pyruvate?
lactate alanine cystein glycine serine trypotophan
glycerol is a ____ substrate
glucogenic
Can you get glucose form fatty acids?
what can you get glucose from?
no.
amino acids, ketones (from fats)
can lipolysis increase glucose production?
yes, can cleave glyerol to be used
need two glyerols / 1 glucose
what is used first for glucose production?
amino acids, then fat can make ketones
how many ATPs are produced during anaerobic glycolysis?
When/where would this occur?
2 ATPS
RBCs
in vigorously working muscles,
with ischemia (stroke/hear attack=loss of blood flow)
and in tumors
what is formed with anaerobic glycolysis?
two lactate (from pyruvate )
how can lactate be used?
- by muscle that created it
- by sending it to heart/resting muscle to form ATP
- by liver, to convert back to pyruvate and generate glucose
What is the Cori cycle?
the catabolism of glucose to lactate in peripheral tissues, then anabolism of lactate to glucose in the liver.
