Eyring H, Johnson F H
Proc Natl Acad Sci U S A. 1971 Oct;68(10):2341-4. doi: 10.1073/pnas.68.10.2341.
A model designated "The elastomeric rack" is discussed with reference to the mechanism of enzyme catalysis and the necessity of large protein molecules in the process. This model, which represents an extension of the earlier "Rack mechanism," stems from experimental evidence demonstrating large volume changes of activation or of reaction accompanying various biochemical reactions and more complicated physiological processes. For reasons discussed, the volume changes, as revealed through the influence of increased hydrostatic pressure on reaction rates and equilibria, prove that there are large conformational changes in the protein which, because of numerous cross links in a complex network, lead to additive stress on the substrate-enzyme complex, and thereby to increased reactivity. The manner in which the model serves to account for the influence of changes in the environment (temperature, pressure, chemical composition, electrical fields) on the activity of the protein catalyst, and the modifying action of particular inhibitory or activating substances, alone or in combination, is briefly discussed. The bearing of various considerations on protein denaturation, excitation of nerve, contraction of muscle, specific precipitation, and the divers physiological processes in living cells, including mutation, cancer, and the degenerative diseases of aging, is also briefly discussed.
文中讨论了一种名为“弹性体支架”的模型，该模型涉及酶催化机制以及该过程中大型蛋白质分子的必要性。此模型是早期“支架机制”的扩展，源于实验证据，这些证据表明，伴随各种生化反应和更复杂的生理过程，活化或反应过程中存在大量体积变化。基于所讨论的原因，通过静水压力增加对反应速率和平衡的影响所揭示的体积变化，证明蛋白质中存在大量构象变化，由于复杂网络中的大量交联，这些变化会对底物 - 酶复合物产生累加应力，从而提高反应活性。文中简要讨论了该模型解释环境变化（温度、压力、化学成分、电场）对蛋白质催化剂活性的影响，以及特定抑制或激活物质单独或组合的修饰作用的方式。还简要讨论了各种因素对蛋白质变性、神经兴奋、肌肉收缩、特异性沉淀以及活细胞中各种生理过程（包括突变、癌症和衰老退行性疾病）的影响。
