<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>Tyrosine phosphorylation involves the introduction of a phosphoryl group into a compound through the formation of an ester bond between a tyrosine residue in the compound and a phosphorus moiety.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>