Thermo Scientific Pierce Citraconic Anhydride reacts with primary amines to to form an amide bond with a terminal carboxyl group. This modification can be reversed using acidic conditions (pH 3-4) or with hydroxylamine.
Citraconic Anhydride (2-methylmaleic anhydride) is used to block primary amine groups at alkaline pH values (pH 7-9). At acidic pH (3-4), the amide linkage is hydrolyzed and citraconic acid is released, revealing the original amine.
- Temporarily block amines to derivatize other parts of the molecule
- Unblock amines using acidic conditions or hydroxylamine
Structure and properties of citraconic anhydride:
- Functional groups: maleic anhydride (amine-reactive)
- Chemical name: 2-methylmaleic anhydride
- CAS number: 616-02-4
- Chemical formula: C5H4O3
- Molecular weight: 112.08
- Form: colorless to slightly yelllow, clear liquid
- Klapper, M.H. and Klotz, I.M. (1972). Acylation with dicarboxylic acid anhydrides. Methods in Enzymology 25:531-52.
Overview of crosslinking and protein modification
Sulfo-NHS-Acetate – permanently block primary amines
TFCS – block and extend primary amines
MS(PEG)n – block and pegylated primary amines