Cavaletto M, Pessione E, Vanni A, Giunta C
Dipartimento di Biologia Animale e dell'Uomo, Università di Torino, Via Accademia Albertina 13, 10123, Torino, Italy.
J Biotechnol. 2001 Nov 17;84(1):87-91. doi: 10.1016/s0168-1656(00)00344-8.
Cobalt-substituted alcohol dehydrogenase 1 was purified from a yeast culture of Saccharomyces cerevisiae. Its reactivity towards different transition metals was tested and compared with the native zinc enzyme. The cobalt enzyme displayed a catalytic efficiency 100-fold higher than that of the zinc enzyme. Copper, nickel and cadmium exerted a mixed-type inhibition, with a scale of inhibition efficiency: Cu(2+)>Ni(2+)>Cd(2+). In general, a higher resistance of the modified protein to the inhibitory action of transition metals was observed, with two orders of magnitude for copper I(50). The presence of nickel in the complexes enzyme-coenzyme-inhibitor-substrate resulted in a decrease of the ampholytic nature of the catalytic site. On the contrary, cadmium and copper exerted an enhancement of this parameter. Electrostatic or other types of interactions may be involved in conferring a good resistance in the basic pH range, making cobalt enzyme very suitable for biotechnological processes.
钴取代的乙醇脱氢酶1是从酿酒酵母的酵母培养物中纯化得到的。测试了其对不同过渡金属的反应性，并与天然锌酶进行了比较。钴酶的催化效率比锌酶高100倍。铜、镍和镉表现出混合型抑制作用，抑制效率顺序为：Cu(2+)>Ni(2+)>Cd(2+)。总体而言，观察到修饰后的蛋白质对过渡金属抑制作用的抗性更高，铜的I(50)有两个数量级。在酶-辅酶-抑制剂-底物复合物中镍的存在导致催化位点两性性质的降低。相反，镉和铜则增强了该参数。静电或其他类型的相互作用可能参与在碱性pH范围内赋予良好的抗性，使得钴酶非常适合生物技术过程。
