Pyruvate Dehydrogenase Phosphatase

Pyruvate dehydrogenase phosphatase is an enzyme that hydrolyzes phosphates from the E1 subunit of the pyruvate dehydrogenase complex. This has the effect of activating the complex (and reversing the phosphorylation by pyruvate dehydrogenase kinase).

The phosphatase is activated by Ca2+ and Mg2+.

Because ATP and ADP differ in their affinities for Mg2+, the concentration of free Mg2+ reflects the ATP/ADP ratio within the mitochondrion. Thus, pyruvate dehydrogenase responds to ATP levels by being turned off when ATP is abundant and further energy production is unneeded.

Unlike the pyruvate dehydrogenase kinase enzyme, which is an integral part of the pyruvate dehydrogenase complex, the phosphatase is loosely bound.

See also: Pyruvate Dehydrogenase Complex, E1, Pyruvate Dehydgrogenase Complex Regulation, Pyruvate Oxidation