Halsey J F, Cebra J J, Biltonen R L
Biochemistry. 1975 Nov 18;14(23):5221-4. doi: 10.1021/bi00694a032.
The thermodynamic quantities of the anti-dinitrophenyl antibody-hapten interaction are reported for rabbit, goat, and guinea pig antibodies. Rabbit and goat antibodies had similar exothermic enthalpy changes for their reaction with 2,4-dinitrophenyl-L-lysine (-13.9 and -14.8 kcal/mol, respectively). The enthalpy change with guinea pig antibody was much less exothermic (-8.7 kcal/mol), and this value was the same for two guinea pig antibody preparations that differed in affinity by almost two orders of magnitude. A heterogeneous goat anti-dinitrophenyl antibody preparation was fractionated on a molecular sieve column in the presence of a bivalent ligand, a procedure that has been reported to separate antibodies according to differences in the depth of interaction with the ligand. The relationship of these differences in apparent site depth to changes in interactions with the hapten tail was examined by comparing the affinities of various fractions for two haptens. The results show that the presumed deeper sites have stronger interactions with the hapten tail. These studies suggest that the heterogeneity of anti-dinitrophenyl antibodies with respect to affinity results from differences in entropy driven lysyl side-chain interactions which arise from a heterogeneity in antigen binding site depth.
报道了兔、山羊和豚鼠抗二硝基苯基抗体与半抗原相互作用的热力学量。兔抗体和山羊抗体与2,4 -二硝基苯基-L-赖氨酸反应时，其放热焓变相似（分别为-13.9千卡/摩尔和-14.8千卡/摩尔）。豚鼠抗体的焓变更少放热（-8.7千卡/摩尔），并且对于两种亲和力相差近两个数量级的豚鼠抗体制剂，该值相同。在二价配体存在的情况下，对一种异质性山羊抗二硝基苯基抗体制剂在分子筛柱上进行分级分离，该方法据报道可根据与配体相互作用深度的差异来分离抗体。通过比较不同级分对两种半抗原的亲和力，研究了这些表观位点深度差异与半抗原尾部相互作用变化之间的关系。结果表明，推测较深的位点与半抗原尾部的相互作用更强。这些研究表明，抗二硝基苯基抗体在亲和力方面的异质性是由抗原结合位点深度的异质性导致的熵驱动的赖氨酰侧链相互作用差异引起的。
