M2-PK: metabolic consequences of the dimeric form

M2-PK: metabolic consequences of the dimeric form

Explanation:

When M2-PK (PKM2) is in the less active dimeric form all phosphometabolites above pyruvate kinase such as glycerate 3-P and fructose 1,6-P2 accumulate and are then available as precursors for synthetic processes such as nucleic acid, phospholipid and amino acid synthesis.

Consequently:

	ADP and GDP levels are high (= substrates of PK).
	ATP and GTP levels are low (= products of the PK reaction).
	Phosphometabolite levels are high.
	Product levels of synthetic processes, such as UTP and CTP are high.
	(ATP+GTP) : (UTP+CTP) ratio is low.
	Energy is provided by glutaminolysis.
	When the fructose 1,6-P2 levels reach a certain high value the dimeric form of M2-PK (PKM2) reassociates to the tetrameric form. Then glucose is converted to lactate until the fructose 1,6-P2 levels drop below a minimum signal level. As a consequence M2-PK (PKM2) dissociates to the dimeric form and this oscillating cycle starts again.

References

Metabolic consequences of the tetrameric form

Pyruvate Kinase isoenymes : M2-PK