Mikolajek Renaud J, Spiess Antje C, Pohl Martina, Büchs Jochen
Biochemical Engineering, RWTH Aachen University, Worringer Weg 1, Aachen 52056, Germany.
Biotechnol Prog. 2009 Jan-Feb;25(1):132-8. doi: 10.1002/btpr.55.
Benzaldehyde lyase (BAL, EC 4.1.2.38) from Pseudomonas fluorescens and benzoylformate decarboxylase (BFD, EC 4.1.1.7) from Pseudomonas putida are thiamine diphosphate-dependent enzymes. These enzymes share a common tetrameric structure and catalyze various C--C-bond forming and breaking reactions. Here we describe a detailed study of the asymmetric synthesis of propioin from propanal catalyzed by BAL or BFD in aqueous solution in a batch reactor. Both enzymes are deactivated in the presence of high concentration of propanal. Compared to BAL, BFD is more stable under reaction conditions as well as during storage. The kinetic studies showed a typical Michaelis-Menten kinetic for BAL with a maximal specific reaction rate of 26.2 U/mg and an unusually high K(M) of 415 mM, whereas the v/[S]-plot for BFD is almost linear in the concentration range (100-1500 mM) investigated. Both enzymes produce propioin with opposite enantiomeric excess: BAL produced the (S)-propioin (ee of 35%), whereas BFD yielded the (R)-enantiomer (ee of 67%).
来自荧光假单胞菌的苯甲醛裂解酶（BAL，EC 4.1.2.38）和来自恶臭假单胞菌的苯甲酰甲酸脱羧酶（BFD，EC 4.1.1.7）是依赖硫胺二磷酸的酶。这些酶具有共同的四聚体结构，并催化各种碳 - 碳键的形成和断裂反应。在此，我们描述了在间歇式反应器中，由BAL或BFD催化丙醛在水溶液中不对称合成丙偶姻的详细研究。在高浓度丙醛存在下，这两种酶都会失活。与BAL相比，BFD在反应条件下以及储存期间更稳定。动力学研究表明，BAL呈现典型的米氏动力学，最大比反应速率为26.2 U/mg，K(M)异常高，为415 mM，而在研究的浓度范围（100 - 1500 mM）内，BFD的v/[S]图几乎呈线性。两种酶产生的丙偶姻对映体过量情况相反：BAL产生（S）-丙偶姻（对映体过量为35%），而BFD产生（R）-对映体（对映体过量为67%）。
