Glycolysis Last 5 Steps

Question 1

Step 6

Glyceraldehyde-3-phosphate dehydrogenase

Answer 1

Converts GLYCERALDEHYDE-3-PHOSPHATE plus NAD+ to (2) 1,3-BISPHOSPHOGLYCERATE + NADH plus H+
Reversible reaction.
NAD+ is reduced to NADH plus H+; phosphate group does not come from ATP.
Reaction is both a phosphorylation and an oxidation-reduction.
1,3-bisphosphoglycerate is a high energy intermediate.
Covalent catalysis (direct bond between enzyme and substrate)

Question 2

Step 7

Phosphoglycerate kinase

Answer 2

Converts (2) 1,3-BISPHOSPHOGLYCERATE + ADP to (2) 3-PHOSPHOGLYCERATE + ATP
Reversible reaction
2 ATP formed (substrate-level phosphorylation)
Transferase reaction
1,3-bisphosphoglycerate is a high energy intermediate

Question 3

Step 8

Phosphoglycerate mutase

Answer 3

Converts (2) 3-PHOSPHOGLYCERATE to (2) 2-PHOSPHOGLYCERATE
Reversible reaction.
Isomerase reaction; phosphate gets moved from C3 to C2 via an active site HIS residue

Question 4

Step 9

Enolase

Answer 4

Converts (2) 2-PHOSPHOGLYCERATE to (2) PHOSPHOENOLPYRUVATE (alkene) + H2O
Reversible reaction
Enolase catalyze a dehydration reaction; H2O is produced.

Question 5

Step 10

Pyruvate kinase

Answer 5

Converts (2) PHOSPHOENOLPYRUVATE plus ADP to (2) PYRUVATE + ATP
Irreversible reaction
Transferase reaction
2 ATP formed (substrate-level phosphorylation)
Pyruvate is a ketone (carbonyl group).