Overview O-Sulfation is a common post-translational modification of tyrosine residues in eukaryotes, but has not been observed in yeast and prokaryotes. Sulfation is limited to secretory and trans-membrane proteins that have passed the trans-Golgi network, where two membrane-bound tyrosylprotein sulfotransferase enzymes catalyze the transfer of sulfate from adenosine 3’-phosphate5’-phosphosulfate to the tyrosine phenol. pKa NC […]


Overview Nitration is a post-translational modification of mostly tyrosine residues that is caused by one-electron oxidation. First, a tyrosine radical is formed by one-electron oxidation followed by a reaction with nitrogen dioxide resulting in 3-nitrotyrosine. pKa NC Loss Gain Deltamass H AA UV-Spec Pattern Acidic7.25 No H NO2 Av: 44.9976M: 44.9851 – Y Yes* – […]


Amidation is one of the most common post-translational modification in which the C-terminal carboxyl group is replaced by an amide group​1–5​. Amidation plays an important role in peptidesand peptide hormones. More than half of all mammalian peptide hormones and more than 80 % of all insect hormones have amidated C-termini​1​. The mechanism of amidation is […]