Konishi-Imamura L, Kim D H, Kobashi K
Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Biochem Int. 1992 Dec;28(4):725-34.
The relationship between the kinetics of the enzyme activity and the structural features of phenolic donor and of acceptor substrates was investigated with a sulfotransferase from Eubacterium A-44, a human intestinal bacterium. The enzyme catalyzed the transfer of the sulfate group from the sulfate esters of phenol having a lower pKa to phenols having a higher pKa. When the Km values for acceptor substrates were measured at their optimal pH, a linear plot for log10Km versus the pKa with a slope of 0.615 was obtained. In addition, it is considered that the effect of pH on the Km values for the various acceptors is due to ionization of free enzyme. The kinetic behavior of bacterial sulfotransferase differed from that of mammalian phenol sulfotransferase.
利用来自人类肠道细菌真细菌A-44的一种磺基转移酶，研究了酶活性动力学与酚类供体及受体底物结构特征之间的关系。该酶催化硫酸基团从pKa较低的苯酚硫酸酯转移至pKa较高的苯酚。当在受体底物的最佳pH下测定其Km值时，得到了log10Km对pKa的线性图，斜率为0.615。此外，认为pH对各种受体Km值的影响是由于游离酶的电离。细菌磺基转移酶的动力学行为与哺乳动物酚磺基转移酶不同。
