Transition state analysis of adenosine nucleosidase from yellow lupin (Lupinus luteus)
作者:Carl Bates、Zachariah Kendrick、Nancy McDonald、Paul C. Kline
DOI:10.1016/j.phytochem.2005.10.006
日期:2006.1
Using a bond order bond energy vibrational analysis, a transition state consisting of a significantly broken C-N bond, formation of an oxocarbenium ion in the ribose ring, a conformation of C3-exo for the ribose ring, and protonation of the heterocyclic base was proposed. This transition state was found to be very similar to the transition state for nucleoside hydrolase, another purine metabolizing
从黄羽扇豆 (Lupinus luteus) 分离的腺苷核苷酶 (EC 3.2.2.7) 的过渡态是基于一系列重原子动力学同位素效应确定的。通过液相色谱/电喷雾质谱法分析用 13C、2H 和 15N 标记的腺苷,以确定动力学同位素效应。发现 [1'-13C]、[1'-2H]、[1.024+/-0.004、1.121+/-0.005、1.093+/-0.004、0.993+/-0.006 和 1.028+/-0.005 的值分别为 2'-2H]、[5'-2H] 和 [9-15N] 腺苷。使用键序键能振动分析,提出了由显着断裂的 CN 键、在核糖环中形成氧碳鎓离子、核糖环的 C3-exo 构象和杂环碱基的质子化组成的过渡态。