Glycolysis Flashcards
Step 1
Substrate: Glucose
Enzyme: Hexokinase
Product: glucose-6-phosphate
1 ATP consumed per rxn
Step 2
Substrate: Glucose-6-phosphate
Enzyme: phosphoglucose isomerase
Product: Fructose-6-phosphate
No ATP used, isomerization rxn
Step 3
Substrate: Fructose-6-phosphate
Enzyme: Phosphofructokinase-1
Product: Fructose-1,6-bisphosphate (aldol)
First committed step of glycolysis, requires 1 ATP per rxn. This is the rate limiting step of glycolysis
Step 4
Substrate: Fructose-1,6-bisphosphate
Enzyme: Aldolase
Product: Glyceraldehyde-3-phosphate and Dihydroxyacetone Phosphate (DHAP is converted to another G3P by triose phosphate isomerase)
-end product of reaction is 2 G3P
Step 5
Substrate: Glyceraldehyde-3-Phosphate
Enzyme: G3P dehydrogenase (uses NAD+ and inorganic phosphate as cofactors)
Product: 1,3-bisphosphoglycerate (high energy phosphate bond)
-all reactions from this step forward are for 2 mol of substrate
Step 6
Substrate: 1,3-bisphosphoglycerate
Enzyme: phosphoglycerate kinase
Product: 3-phosphoglycerate
-enz moves high energy phosphate from substrate to ADP, making ATP (2 mol per mol glucose)
Step 7
Substrate: 3-phosphoglycerate
Enzyme: phosphoglyceromutase
Product: 2-phosphoglycerate
Step 8
Substrate: 2-phosphoglycerate
Enzyme: enolase (dehydration reaction, -h20)
Product: Phosphoenolpyruvate
-dehydration reaction (makes phosphate on C2 more apt leaving group)
Step 9
Substrate: Phosphoenolpyruvate
Enzyme: pyruvate kinase
Product: Pyruvate
-pyr kinase removes high energy phosphate and gives it to ADP, giving 2 more mol ATP per mol glucose.
Glycolysis Net Reaction
Glucose+ 2NAD+ 2Pi +2ADP ===> 2 Pyruvate + 2 ATP + 2 NADH +4 H+ + 2H20
Regulation of Glycolysis
Hexokinase (glucokinase in liver)==> G6P-
PFK-1==> ATP-, AMP+, citrate-
phosphoglycerate kinase==> ATP-, NADH-
