Liquid disordered phase

There is a large cholesterol concentration gradient in cells from 0-5 mol% in the ER membrane to 25-40 mol% in the plasma membrane [12], Cholesterol has a condensing effect on liquid-crystalline bilayers, causing increased rigidity and thickness [13]. At high concentrations, cholesterol induces an intermediate liquid-ordered phase between the gel and liquid-disordered phases [13]. A number of... 

Marsh (38) has listed several measured values of the elastic moduli of lipid bilayers. Typically, the area compressibility moduli are in the range of 200-250 mNm for fully hydrated symmetric bilayers in the L phase prepared from phosphatidylcholines, and they are not very dependent on the degree of saturation of the acyl chains. Cholesterol has a significant effect on the area compressibility modulus of a bilayer. Thus, AT A for bilayers of l-stearoyl-2-oleoylphosphatidylcholine (SOPC) increases from 235 mN m in the absence of cholesterol (La liquid-disordered phase) to 640 mN m in bilayers... 

The lipids in a lipid bilayer may translocate across the bilayer from one monolayer to the apposed monolayer. This transmembrane translocation process, which is also known as flip-flop, is slow for lipids with large polar head groups such as glyc-erolipids and sphingophospholipids but can be fast in the case of lipids with very small polar moieties such as cholesterol. Typical first-order rate constants for transmembrane translocation of a phospholipid-like molecule in liquid-disordered phase bilayers prepared from l-palmitoyl-2-oleoylphosphatidylcholine (POPC) are s and may be about 10-fold slower in... 

Liquid disordered phase In lipids, a meso-phase state in which lipid molecules are loosely packed together, diffuse rapidly, and sample many conformational states. 

Bilayer melting temperature (Tm) The temperature at which phospholipid bilayers in the solid ordered (gel) phase undergo a phase transition to a liquid disordered phase. This transition be broad or might pass via an intermediate phase. 

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