Pyruvate Kinase: Step 9 of Glycolysis Flashcards

1
Q

What reaction does pyruvate kinase catalyze?

A

The conversion of phosphoenolpyruvate to pyruvate (and, with this, the synthesis of ATP from ADP).

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2
Q

Is the reaction of PEP to pyruvate reversible?

A

No

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3
Q

Why are 4 molecules of ATP generated in the second half of glycolysis?

A

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.

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4
Q

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.

A

True

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5
Q

What are the two reaction steps in the conversion of PEP to pyruvate?

A

1) Hydrolysis (release of the high energy phosphate)

2) Tautomerization: enol to ketone

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6
Q

Which step in the reaction of PEP to pyruvate releases the most free energy?

A

Tautomerization of enol pyruvate to keto pyruvate

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7
Q

What metal cofactors are required for pyruvate kinase (PK) to catalyze PEP to pyruvate?

A

K+ and Mg2+

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