Citraconic anhydride reacts with primary amines and blocks them by creating an amide linkage and a terminal carboxylate.
The linkage is stable at neutral to alkaline pH (pH >7) and at acidic conditions (pH 4) the amide linkage is rapidly hydrolyzed to release the citraconic acid and free the amines. The block by citraconic anhydride can also be reveresed by treatment with hydroxylamine. This property makes citraconic anhydride a very useful tool for blocking free amines in proteins and other biomolecules.
- Reversible blocking of primary amines
- Reactive towards primary amines
- Synonym: 2-methylmaleic anhydride
- Empirical formula:C5H4O3
- CAS # 616-02-4
- Molecular weight: 112.08
- Form: Colorless to slight yellow, clear liquid
- Temporarily block amines to allow derivatization of other parts of the molecule.
- Block removed by shifting to acidic conditions (pH3-4) or treatment with hydroxylamine