磷脂酰胆碱在甘油中的叉指相热力学。
Thermodynamics of interdigitated phases of phosphatidylcholine in glycerol.
作者信息
Swamy M J, Marsh D
机构信息
Max-Planck-Institut für biophysikalische Chemie, Abteilung Spektroskopie, Göttingen, Germany.
出版信息
Biophys J. 1995 Oct;69(4):1402-8. doi: 10.1016/S0006-3495(95)80009-3.
Comparison of the electron spin resonance spectra of phosphatidylcholines spin-labeled in the sn-2 chain at a position close to the polar region and close to the methyl terminus indicate that symmetrical saturated diacyl phosphatidylcholines with odd and even chain lengths from 13 to 20 C-atoms (and probably also 12 C-atoms) have gel phases in which the chains are interdigitated when dispersed in glycerol. The chain-length dependences of the chain-melting transition enthalpies and entropies are similar for phosphatidylcholines dispersed in glycerol and in water, but the negative end contributions are smaller for phosphatidylcholines dispersed in glycerol than for those dispersed in water: d delta Ht/dCH2 = 1.48 (1.43) kcal.mol-1, d delta St/dCH2 = 3.9 (4.0) cal.mol-1K-1, and delta H o = -12.9 (-15.0) kcal.mol-1, delta S o = -29 (-40) cal.mol-1K-1, respectively, for dispersions in glycerol (water). These differences reflect the interfacial energetics in glycerol and in water, and the different structure of the interdigitated gel phase.
对在靠近极性区域和靠近甲基末端的sn-2链上进行自旋标记的磷脂酰胆碱的电子自旋共振光谱进行比较表明，具有13至20个碳原子（可能还有12个碳原子）奇数和偶数链长的对称饱和二酰基磷脂酰胆碱在分散于甘油中时具有凝胶相，其中链相互交错。分散在甘油和水中的磷脂酰胆碱的链熔化转变焓和熵的链长依赖性相似，但分散在甘油中的磷脂酰胆碱的负端贡献比分散在水中的小：对于分散在甘油（水）中的磷脂酰胆碱，dΔHt/dCH2 = 1.48（1.43）kcal·mol-1，dΔSt/dCH2 = 3.9（4.0）cal·mol-1K-1，以及ΔHo = -12.9（-15.0）kcal·mol-1，ΔSo = -29（-40）cal·mol-1K-1。这些差异反映了甘油和水中的界面能量学以及交错凝胶相的不同结构。
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