Finegold L, Singer M A
Biochim Biophys Acta. 1986 Mar 13;855(3):417-20. doi: 10.1016/0005-2736(86)90086-6.
We report the peak temperatures and enthalpies of the main (gel to liquid crystal) transitions and 's-transitions' of symmetric saturated PC's (CnPC) with n varying from 12 to 22, where s-transition is defined as the transition between metastable and stable phases. The line for s-transition peak temperature versus n (t = 1.98n -16.0 degrees C) crosses the corresponding pre- and main-transition curves between n = 12 and 14. We also find that the metastability pattern for lipids of n less than 14 is different to that for n greater than 14 (and is similar to that of the phosphatidylethanolamine analogs). For n greater than 14 the enthalpy of the s-transition decreases with increasing n and extrapolates to zero above n = 20, implying that the s-(orthorhombic) and gel (quasi-hexagonal) phases become identical. That simultaneous gel-liquid crystal transition and metastability is restricted to the range n = 12 to 20 may be correlated with the predominance in natural lipids of these acyl chain lengths.
我们报告了对称饱和磷脂酰胆碱（CnPC，其中n从12变化到22）主要（凝胶态到液晶态）转变以及“s-转变”（s-转变定义为亚稳相和稳定相之间的转变）的峰值温度和焓。s-转变峰值温度与n的关系曲线（t = 1.98n - 16.0℃）在n = 12和14之间与相应的预转变曲线和主要转变曲线相交。我们还发现，n小于14的脂质的亚稳模式与n大于14的脂质不同（并且与磷脂酰乙醇胺类似物的亚稳模式相似）。对于n大于14的情况，s-转变的焓随n的增加而降低，并且在n = 20以上外推至零，这意味着s-（正交晶系）相和凝胶（准六方）相变得相同。凝胶-液晶态同时转变和亚稳性仅限于n = 12至20的范围，这可能与这些酰基链长度在天然脂质中的优势有关。
