Jacques Steven L
Oregon Health and Science University, Department of Dermatology, 20000 NW Walker Road, Beaverton, Oregon 97006, USA.
J Biomed Opt. 2006 Jul-Aug;11(4):041108. doi: 10.1117/1.2343437.
Thermal transitions in biological tissues that have been reported in the literature are summarized in terms of the apparent molar entropy (DeltaS) and molar enthalpy (DeltaH) involved in the transition. A plot of DeltaS versus DeltaH for all the data yields a straight line, consistent with the definition of free energy, DeltaG=DeltaH+TDeltaS. Various bonds may be involved in cooperative bond breakage during thermal transitions; however, for the sake of description, the equivalent number of cooperative hydrogen bonds can be cited. Most of the tissue data behave as if 10 to 20 hydrogen bonds are cooperatively broken during coagulation, with one transition, the expression of heat shock protein, involving 90 cooperative hydrogen bonds. The data are consistent with DeltaS=a+bDeltaH, where a=-327.5 J(mol K) and b=31.47 x 10(-4) K(-1). If each additional hydrogen bond adds 19 x 10(3) Jmol to DeltaH, then each additional bond adds 59.8 J(mol K) to DeltaS. Hence, the dynamics of irreversible thermal transitions can be described in terms of one free parameter, the apparent number of cooperative hydrogen bonds broken during the transition.
文献中报道的生物组织热转变，根据转变过程中涉及的表观摩尔熵（ΔS）和摩尔焓（ΔH）进行了总结。所有数据的ΔS对ΔH作图得到一条直线，这与自由能的定义ΔG = ΔH + TΔS一致。热转变过程中协同键断裂可能涉及各种化学键；然而，为了描述方便，可以引用等效的协同氢键数量。大多数组织数据表现得就好像在凝固过程中有10到20个氢键协同断裂，而热休克蛋白的表达这一转变过程涉及90个协同氢键。这些数据符合ΔS = a + bΔH，其中a = -327.5 J/(mol·K)，b = 31.47×10⁻⁴ K⁻¹。如果每个额外的氢键使ΔH增加19×10³ J/mol，那么每个额外的键使ΔS增加59.8 J/(mol·K)。因此，不可逆热转变的动力学可以用一个自由参数来描述，即转变过程中协同断裂的氢键表观数量。
