Marsden Stefan R, Gjonaj Lorina, Eustace Stephen J, Hanefeld Ulf
Biokatalyse, Afdeling Biotechnologie Technische Universiteit Delftvan der Maasweg 92629 HZ Delft The Netherlands.
ChemCatChem. 2017 May 23;9(10):1808-1814. doi: 10.1002/cctc.201601649. Epub 2017 Apr 13.
Transketolase catalyzes asymmetric C-C bond formation of two highly polar compounds. Over the last 30 years, the reaction has unanimously been described in literature as irreversible because of the concomitant release of CO if using lithium hydroxypyruvate (LiHPA) as a substrate. Following the reaction over a longer period of time however, we have now found it to be initially kinetically controlled. Contrary to previous suggestions, for the non-natural conversion of synthetically more interesting apolar substrates, the complete change of active-site polarity is therefore not necessary. From docking studies it was revealed that water and hydrogen-bond networks are essential for substrate binding, thus allowing aliphatic aldehydes to be converted in the charged active site of transketolase.
转酮醇酶催化两种高极性化合物形成不对称碳-碳键。在过去30年里，由于使用羟基丙酮酸锂（LiHPA）作为底物时会伴随二氧化碳的释放，该反应在文献中一直被一致描述为不可逆反应。然而，经过更长时间的反应跟踪，我们现在发现它最初是受动力学控制的。与之前的观点相反，对于合成上更具吸引力的非极性底物的非天然转化，因此并不需要完全改变活性位点的极性。对接研究表明，水和氢键网络对于底物结合至关重要，从而使得脂肪醛能够在转酮醇酶的带电荷活性位点中发生转化。
