Tyrosine sulfation
Tyrosine sulfation is a posttranslational modification where a sulfate group is added to a tyrosine residue of a protein molecule. Secreted proteins and extracellular parts of membrane proteins that pass through the Golgi apparatus may be sulfated. Sulfation was first discovered by Bettelheim in bovine fibrinopeptide B in 1954 and later found to be present in animals and plants but not in prokaryotes or in yeast.
Function
Sulfation plays a role in strengthening protein-protein interactions. Types of human proteins known to undergo tyrosine sulfation include adhesion molecules, G-protein-coupled receptors, coagulation factors, serine protease inhibitors, extracellular matrix proteins, and hormones.
Tyrosine O-sulfate is a stable molecule and is excreted in urine in animals. No enzymatic mechanism of tyrosine sulfate desulfation is known to exist.
By knock-out of TPST genes in mice, it may be observed that tyrosine sulfation has effects on the growth of the mice, such as body weight, fecundity, and postnatal viability.