Pyruvate Kinase: Step 9 of Glycolysis Flashcards
What reaction does pyruvate kinase catalyze?
The conversion of phosphoenolpyruvate to pyruvate (and, with this, the synthesis of ATP from ADP).
Is the reaction of PEP to pyruvate reversible?
No
Why are 4 molecules of ATP generated in the second half of glycolysis?
Fructose 1,6-bisphosphate is effectively converted to 2 molecules of GAP (because the DHAP is converted to GAP as GAP is used downstream). So the second half of glycolysis effectively happens for two molecules, producing 2 ATP at the 1,3-BPG to 3PG step and 2 ATP at the PEP to pyruvate step.
True or false: The energy derived from the conversion of PEP to pyruvate is highly exergonic and provides enough energy for substrate level ATP synthesis.
True
What are the two reaction steps in the conversion of PEP to pyruvate?
1) Hydrolysis (release of the high energy phosphate)
2) Tautomerization: enol to ketone
Which step in the reaction of PEP to pyruvate releases the most free energy?
Tautomerization of enol pyruvate to keto pyruvate
What metal cofactors are required for pyruvate kinase (PK) to catalyze PEP to pyruvate?
K+ and Mg2+