Critical micelle concentration (CMC)

Schematic of a phospholipid micelle

Critical micelle concentration (CMC) is defined as the concentration of detergents above which micelles are spontaneously formed. The CMC is important in biology because at concentrations above it the detergents form complexes with lipophilic proteins. Below this borderline, detergents merely partition into membranes without solubilising membrane proteins.

Detergent	CMC (mM)	MW (-H2O)	Type
BRIJ 35	0.09	~1200	non-ionic
NP-40	0.05-0.3	603	non-ionic
Triton X-100	xxx	yyy	non-ionic
Tween 20	0.059	-	non-ionic
SDS	7-10	288.5	ionic
CHAPS	6-10	614.9	zwitterionic

Sources

• Biological detergents, Calbiochem Guide
• Commonly used detergents, Frost Lecture, UFL

See also

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