# What is phosphorylation and why is it important?

#### Risposta:

The covalent addition of a phosphate group to a molecule.

#### Spiegazione:

La fosforilazione is an important mechanism by which the activity of proteine can be altered after they are formed. A phosphate group (PO""_4^(3-)) is added to a protein by specific enzymes called kinases. This phosphate group is usually provided by ATP, the energy carrier of the cell.