CHAPSO (3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonate)

CHAPSO, or 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonate, is a zwitterionic detergent commonly used in biochemical and biophysical research. It is widely employed for membrane protein solubilization, stabilization, and purification. CHAPSO is known for its mildness and ability to preserve the structural integrity and functionality of membrane proteins during extraction. Its unique properties make it suitable for a variety of applications, including protein crystallization, spectroscopy, and structural biology studies. With its versatile and effective solubilization capabilities, CHAPSO is a valuable tool for researchers working with membrane proteins.

Features of CHAPSO include:

• Zwitterionic detergent
• Gentle—enabling preservation of native conformation and activity
• Effectively disrupts lipid-protein interactions
• Exhibits low critical micelle concentration (CMC)
• High-purity compound with low UV absorptivity

Properties

• CMC: (H₂O) ∼8 mM (0.50%)
• Aggregation number: (H₂O) ∼11
• Purity: ≥99% (by HPLC analysis)
• pH: 5–8 (1% solution in water)
• Solubility: ≥0.5 M (in water at 20 °C)
• Fluorescence: <10% (0.1% solution in water at 345 nm)
• Absorbance of a 1% solution in water: 260 nm: <0.06, 280 nm: <0.04, 340 nm: <0.02