Editing Tyrosine (section)

=== Phosphorylation and sulfation ===
Some of the tyrosine residues can be ''tagged'' (at the hydroxyl group) with a phosphate group ([[phosphorylation|phosphorylated]]) by [[protein kinase]]s. In its phosphorylated form, tyrosine is called '''phosphotyrosine'''. Tyrosine phosphorylation is considered to be one of the key steps in signal transduction and regulation of enzymatic activity.  Phosphotyrosine can be detected through specific [[antibody|antibodies]].  Tyrosine residues may also be modified by the addition of a sulfate group, a process known as [[tyrosine sulfation]].<ref name="pmid17046811">{{cite journal | vauthors = Hoffhines AJ, Damoc E, Bridges KG, Leary JA, Moore KL | title = Detection and purification of tyrosine-sulfated proteins using a novel anti-sulfotyrosine monoclonal antibody | journal = The Journal of Biological Chemistry | volume = 281 | issue = 49 | pages = 37877–87 | date = December 2006 | pmid = 17046811 | pmc = 1764208 | doi = 10.1074/jbc.M609398200 | doi-access = free }}</ref> [[Tyrosine sulfation]] is catalyzed by [[tyrosylprotein sulfotransferase]] (TPST).  Like the phosphotyrosine antibodies mentioned above, antibodies have recently been described that specifically detect sulfotyrosine.<ref>{{cite journal | vauthors = Kanan Y, Hamilton RA, Sherry DM, Al-Ubaidi MR | title = Focus on molecules: sulfotyrosine | journal = Experimental Eye Research | volume = 105 | pages = 85–6 | date = December 2012 | pmid = 22406006 | pmc = 3629733 | doi = 10.1016/j.exer.2012.02.014 }}</ref>