Tyrosine phosphorylation

Tyrosine phosphorylation is the addition of a phosphate (PO₄³⁻) group to the amino acid tyrosine on a protein. It is one of the main types of protein phosphorylation. This transfer is made possible through enzymes called tyrosine kinases. Tyrosine phosphorylation is a key step in signal transduction and the regulation of enzymatic activity.