ADP-Ribosylation

ADP-ribosylation is a reversible post-translational modification in which one (mono-ADP-ribosylation) or multiple (poly-ADP-ribosylation) ADP-ribose moieties are attached onto a substrate protein by ADP ribosyltransferases. mono-ADP-Ribosylation Overview mono-ADP-ribosylation is a common post-translational modification, where an ADP-ribose moiety is transferred from NAD+ to the substrate protein under the release of nicotinamide. The transfer of ADP-ribose occurs onto […]

Citrullination

Overview Citrulline is a non-proteinogenic amino acid that is produced through post-translational deimination of peptidyl-arginine. Peptidyl-arginine deiminases catalyze the hydrolysis of a guanido group into an urea group. This modifications affects the formation of hydrogen bonds and therefore protein folding. pKa NC Loss Gain Deltamass H AA UV-Spec Pattern – No NH O Av: 0.9848M: […]

Prenylation

Prenylation covers two post-translational modifications in which one or two isoprenoid moieties, either farnesyl or geranylgeranyl moieties, are attached to a conserved cysteine residue via thioether bond at or near the C-terminus. Most prenylated proteins contain a CAAX motif at the C-terminus. The CAAX motif is a sequence of four amino acids, where “C” stands […]

O-Sulfation

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 […]

Nitration

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

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 […]