Liquid ordered phase

The liquid ordered phase is a liquid crystalline phase of biological importance. It occurs whenever there is cholesterol and phospholipid and/or sphingolipids e.g sphingomyelin present. This phase has been related to lipid rafts that may exist in plasma membranes.

Definition
The liquid ordered phase can be defined as:


 * fluid and lamellar phase
 * acyl hydrocarbon chains are in the all-trans state
 * rapid lateral diffusion
 * 2H-NMR quadrupolar splitting is ca. 50kHz
 * WAXS scattering pattern centered by broad diffraction peak at 4.2Å

History
This was first called the liquid ordered phase by Ipsen et al. (1987). However, it has also been called the LGI subgel phase by Huang et al. (1993) and the β phase by Vist and Davis (1990).