Citraconic anhydride (Methylmaleic anhydride) is a derivative of maleic anhydride. Citraconic anhydride reversibly blocks protein amino groups, stabilizes specific enzymes and improves their catalytic performance, or reverses the effects of formalin fixation in tissue sections. Citraconic anhydride is irritating to the skin and eyes.

Physicochemical Properties

Molecular Formula	C5H4O3
Molecular Weight	112.08
CAS #	616-02-4
PubChem CID	12012
Appearance	Colorless to light yellow liquid
Density	1.247 g/mL at 25 °C(lit.)
Boiling Point	213-214 °C(lit.)
Melting Point	6-10 °C(lit.)
Flash Point	215 °F
Index of Refraction	n20/D 1.471(lit.)
LogP	0.016
Hydrogen Bond Acceptor Count	3
Heavy Atom Count	8
Complexity	178
Defined Atom Stereocenter Count	0
SMILES	O1C(C([H])=C(C1=O)C([H])([H])[H])=O
Synonyms	Methylmaleic anhydride
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

References

[1]. Hermanson G T. Chapter 2-functional targets for bioconjugationJ. Bioconjugate Techniques, 2013, 3: 127-228.

Solubility Data

Solubility (In Vitro)

DMSO : ≥ 100 mg/mL (~892.22 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (22.31 mM)(saturation unknown) in 10% DMSO 40% PEG300 5% Tween-80 45% Saline (add these co-solvents sequentially from left to right, and one by one),clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution and add it to 400 μL PEG300, mix well; then add 50 μL Tween-80 to the above system, mix well; then continue to add 450 μL of normal saline to make up to 1 mL. Preparation of normal saline: Dissolve 0.9 g of sodium chloride in ddH₂O and make up to 100 mL to obtain a clear and transparent normal saline solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (22.31 mM)(saturation unknown) in 10% DMSO 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one),clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution and add it to 900 μL corn oil and mix well. Solubility in Formulation 3: ≥ 2.5 mg/mL (22.31 mM)(saturation unknown) in 10% DMSO 90% Saline (add these co-solvents sequentially from left to right, and one by one),clear solution. For example, if 1 mL of working solution is to be prepared,  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	8.9222 mL	44.6110 mL	89.2220 mL
	5 mM	1.7844 mL	8.9222 mL	17.8444 mL
	10 mM	0.8922 mL	4.4611 mL	8.9222 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.