Glycolysis Flashcards
Insulin stimulates what enzyme in glycolysis
Glucokinase locks glucose in the liver
AMP stimulates what enzyme in glycolysis
PFK-1 makes fructose 1,6 bisphophate
What has a negative effect on PFK-1
Citrate ATP
What is the last step of glycolysis
Phosphoenolpyruvate –> Pyruvate via pyruvate kinase
Pyruvate kinase deficiency
Partial enzyme defect Hemolytic anemia increased 2,3-BPG no Heinz bodies
RBC are capable of only doing
glycolysis HMP shunt
Why does pyruvate kinase deficiency get hemolytic anemia
can’t do glycolysis to get ATP to power cation pumps
In methemoglobin iron is in the
+3 state
In hemoglobin iron is in the
+2 state
RBC need the NADH from glycolysis to
change methemoglobin back to hemoglobin
RBC use the HMP shunt bc
to make NADPH an antioxidant
Increase of 2,3 BPG will cause
O2 sat curve to shift to the right decreased O2 affinity for Hb more O2 unloading off Hb
After a high carb meal what will you see in glycolysis
Increased ATP Decreased PFK-1 decreased glycolysis (unless overrides by PFK-2)
What is the first enzyme in glycolysis
Hexokinase glucokinase (liver only)
What does PFK-2 do
Fructose-6P –> Fructose 2, 6 P
What does PFK-1 do
Fructose-6P –> Fructose 1,6 bis P
What is the role of Fructose 2,6-P
Will overcome any inhibition of PFK-1 by ATP or citrate to make Fructose 1,6-BP Complete glycolysis to make pyruvate to do FA synthesis ONLY IN LIVER
What stimulates PFK-2
Insulin
Insulin stimulates what enzymes in glycolysis
hexokinase PFK-2 PFK-1 indirectly
What inhibits PFK-2
Glucagon indirectly inhibits PFK-1 in liver
In the presence of O2 how is NADH recycled to NAD+ to continue glycolysis
in the mitochondria electrons from pyruvate taken off and put on O2 to make water Pyruvate goes to mitochondria –> acetyl-coA via pyruvate DH to go into TCA cycle makes more ATP and CO2
Without O2, how is NADH recycled to NAD+ to continue glycolysis
lactate DH converts pyruvate to lactate in the cytoplasm
Which glycolysis enzymes require ATP
hexokinase/glucokinase
PFK-1
Which glycolysis enzymes make ATP
Phosphoglycerate kinase (1,3-BPG to 3-PG)
Pyruvate kinase (PEP to pyruvate)
Which is induced by insulin, glucokinase or hexokinase
glucokinase
Which has a higher Km (low affinity), hexokinase or glucokinase
Glucokinase
Which has a higher Vmax (increased capacity), hexokinase or glucokinase
Glucokinase
Which has feedback inhibition by G6P, hexokinase or glucokinase
hexokinase
Biochemical basis in fasting state
- Increased glucagon will increasing cAMP
- increase protein kinase A
- increase in FBPase-2
- decrease PFK-2
- less glycolysis, more gluconeogenesis
Biochemical basis of fed state
- increase insulin will decrease cAMP
- decrease protein kinase A
- decrease FBPase-2
- increase PFK-2
- more glycolysis, less gluconeogenesis
Pyruvate DH is active in what state
fed state
Pyruvate DH is activated by
increase NAD+/NADH ratio, ADP, Calcium
what is PDH complex deficiency
Build up of pyruvate that gets shunted to lactate (via LDH) and alanine (via ALT)
Characteristics of PDH deficiency
- neurologic defects
- lactic acidosis
- increase serum alanine in infancy
How to treat PDH deficiency
increase intake of ketogenic nutrients
- high fat content
- increase leucine and lysine
