Phosphoprotein phosphatase

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Phosphoprotein phosphatase is an insulin stimulated enzyme which removes the phosphate groups from certain phosphorylated enzymes.

[edit] Signifiance

The activites of the enzyme is stimulated by the hormone, insulin, which is a signal of high blood glucose level.

The control of many enzymes involves covalent modifications, such as partial hydrolysis. Another method of control is through reversible phosphorylation of hydroxyl groups of specific amino acid residues in the polypeptide chain. Phosphorylation from ATP is catalyzed by specific protein kinase.

The activated enzyme desphosphorylates the phosphorylase kinase, glycogen synthase and glycogen phosphorylase. The activities of the phosphorylase kinase and glycogen phosphorylase is inhibited; the glycogen synthase is activated. As a result, the synthesis glycogen is enhanced and glycogenolysis is inhibited in the reciprocal control.