Hur Sun, Bruice Thomas C
Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
J Am Chem Soc. 2003 Sep 3;125(35):10540-2. doi: 10.1021/ja0357846.
Standard free energies for formation of ground-state reactive conformers (DeltaGN degrees ) and transition states (DeltaG) in the conversion of chorismate to prephenate in water, B. subtilis mutase, E. coli mutase, and their mutants, as well as a catalytic antibody, are related by DeltaG = DeltaGN degrees + 16 kcal/mol. Thus, the differences in the rate constants for the water reaction and catalysts reactions reside in the mole fraction of substrate present as reactive conformers (NACs). These results, and knowledge of the importance of transition state stabilization in other cases, suggest a proposal that enzymes utilize both NAC and transition state stabilization in the mix required for the most efficient catalysis.
在水中，分支酸转化为预苯酸的过程中，枯草芽孢杆菌变位酶、大肠杆菌变位酶及其突变体以及一种催化抗体形成基态反应性构象体（ΔG°N）和过渡态（ΔG）的标准自由能，通过ΔG = ΔG°N + 16千卡/摩尔相关联。因此，水反应和催化剂反应速率常数的差异在于以反应性构象体（NACs）形式存在的底物的摩尔分数。这些结果，以及在其他情况下过渡态稳定化重要性的知识，提出了一种观点，即酶在最有效催化所需的混合物中同时利用NAC和过渡态稳定化。
