Skip to content
Login Register

#transition temperature

2 public questions tagged with this topic.

Properties of Plasma Membrane

Which molecule has the lowest transition temperature (Tm)?

Transition temperature dependence reflects chain packing efficiency influenced by length unsaturation. DOPC dioleoyl phosphatidylcholine contains two eighteen carbon chains each with cis delta nine double bond bending chain thirty degrees creating double kinks and large cross sectional volume reducing van der Waals contacts. Its Tm about minus seventeen to minus twenty Celsius lowest among common PCs. POPC one palmitoyl saturated sixteen plus one oleoyl unsaturated Tm minus two, DPPC dipalmitoyl two saturated sixteen packs tightly all trans Tm forty one due to high cooperative enthalpy, DMPC d

Ref: Lewis et al., Biochemistry 1987, Phosphatidylcholine Tm table DOPC lowest.

View Details
Properties of Plasma Membrane

Which of the following affects the transition temperature (Tm) of membranes?

Phase transition of lipid bilayers from lamellar gel L beta where acyl chains fully extended ordered tight orthorhombic packing low mobility to liquid crystalline L alpha where chains disordered gauche isomers high mobility monitored by differential scanning calorimetry DSC exhibiting endothermic peak at Tm and by fluorescence anisotropy probes DPH TMA-DPH showing sharp decrease. Factors affecting Tm: chain length longer sixteen to eighteen carbons increases van der Waals interactions raising Tm dipalmitoyl phosphatidylcholine sixteen zero Tm forty one degrees centigrade distearoyl eighteen ze

Ref: McElhaney, Lipid Phase Transition and Chain Length Effect, Biochim Biophys Acta 1984.

View Details