Glycolysis Flashcards
Where does glycolysis take place?
In the cytoplasm
What are the products of glycolysis?
2 pyruvate
2 NADH
2 ATP
Glucose—-> ?
What enzyme?
Glucose —-> glucose 6 phosphate
Hexokinase
ATP—-> ADP
In the liver, what is the enzyme called converting glucose to glucose 6 phosphate?
Glucokinase
Glucose-6-phosphate—-> ?
Enzymes?
Glucose-6-phosphate—-> Fructose-6-phosphate
Phosphohexose isomerase
Fructose-6-phosphate—-> ?
Enzymes?
Fructose-6-phosphate—->fructose-1,6-bisphosphate
PFK-1 (phosphofructokinase-1)
ATP—->ADP
What can fructose-1,6-bisphosphate become?
Dihydroxyacetone phosphate
3-phosphoglyceraldehyde
Fructose-1,6-bisphosphate —> dihydroxyacetone phosphate —> 3-phosphoglyceraldehyde
Enzymes for each step?
Aldolase
Triose phosphate isomerase
Fructose-1,6-bisphosphate ——> 3-phosphoglyceraldehyde?
Enzyme?
Fructose bisphosphate aldolase
3-phosphoglyceraldehyde —-> ?
Enzymes?
3-phosphoglyceraldehyde —-> 1,3-bisphosphoglycerate
Glyceraldehyde-3-phosphate dehydrogenase
NAD+ —> NADH
1,3-bisphosphoglycerate —-> ?
Enzymes?
1,3-bisphosphoglycerate —-> 3-phosphoglycerate
Phosphoglycerate kinase
ADP—> ATP
3-phosphoglycerate —-> ?
Enzyme?
3-phosphoglycerate —-> 2 phosphoglycerate
Phosphoglycerate mutase
2 phosphoglycerate —-> ?
Enzyme?
2 phosphoglycerate —-> phosphoenolpyruvate
Enolase
phosphoenolpyruvate —-> ?
Enzyme?
phosphoenolpyruvate —-> pyruvate
Pyruvate kinase
ADP—-> ATP
Where does pyruvate go to?
Lactate (anaerobic)
Krebs cycle (aerobic)
Which 2 enzymes are regulated?
Hexokinase
PFK-1
What is Hexokinase activity controlled by?
Controlled by glucose-6-phosphate
Reversible reaction
More product, slower rate of reaction
What is the main regulator/rate limiting step of glycolysis?
PFK-1
What is PFK-1 effected by?
Allosterically - not affected by main active site
AMP (adenosine monophosphate)
How does AMP effect PFK-1?
It is an allosteric activator (modifies the AS of the enzyme so affinity for substrate increases)
Increased AMP = increased PFK-1 action = increased affinity for fructose 6 phosphate
How does ATP affect PFK-1?
ATP is an allosteric inhibitor (decreases affinity for substrate to bind)
Inhibited by ATP
Increased ATP = decreased PFK-1
Decreased ATP = increased PFK-1
Which 2 steps produce ATP?
1,3-bisphosphoglycerate —-> 3-Phosphoglycerate
Phosphoenolpyruvate — > pyruvate
What does insulin affect and how?
Insulin increases rate of glycolysis (affects PFK-1 indirectly)
Is glycolysis aerobic or anaerobic?
Anaerobic (doesn’t need O2)
What does anaerobic resp produce?
Produces lactate (toxic) and NAD+ (so glycolysis can continue) and a little ATP
