CHAPS

CHAPS is a cholic acid-derived, sulfobetaine-type zwitterionic detergent and micelle-forming agent. CHAPS exhibits properties of weak cationic or nonionic surfactants in different solution systems, undergoes micellization, and forms small, loose hydrophilic aggregates that are temperature-dependent. CHAPS stabilizes mononucleosomes under different ionic strengths, reduces nucleosome sequence specificity, promotes sliding of histone cores along DNA, solubilizes Tamm‑Horsfall protein to reduce its interference with urinary exosome isolation, and maintains vesicle structure and the activity of related proteins at the same time. CHAPS is used to recover native folded fusion proteins, enhance the binding capacity of GST fusion proteins, and restore GST enzyme activity. However, CHAPS cannot refold proteins denatured by urea, guanidine hydrochloride or heat, nor can it construct the structure of intrinsically disordered proteins. CHAPS is commonly used in research on the separation and purification of membrane proteins^[1][2][3][4]. In Vitro:CHAPS forms low aggregation number (5.4-6.7) micelles with cmc values dependent on solvent and temperature (U-shaped cmc vs temperature curve with minimum at ~295 K) and ΔH_m⁰ transitioning from endothermic to exothermic with increasing temperature in aqueous solutions, NaCl solutions, and buffer solutions^[1].
CHAPS (16-4.8 mM; 1-120 h) stabilizes reconstituted mononucleosomes (assembled with human histones H2A, H2B, H3, H4 on 601 sequence DNA) at 0.4 nM concentration at 0°C without altering their structure, with 16 μM preventing dissociation for 1 hour, 1.6 mM maintaining over 50% intact nucleosomes for 120 hours, and 4.8 mM maintaining over 70% intact nucleosomes for 120 hours^[2].
CHAPS (1% (w/v); overnight at 4°C) treatment of pooled urine-derived exosomal pellets (P18, P200) preserves vesicle morphology, exosomal marker distribution, and nephrilysin activity while removing interfering proteins like THP and albumin^[3].