Rozengart E V, Basova N E, Khovanskikh A E, Epshteĭn L M
Zh Evol Biokhim Fiziol. 1996 Jul-Aug;32(4):384-92.
It is the first time when the substrate specificity is considered as a complex phenomenon, taking into account an influence of substrate structure on the rate of enzymatic hydrolysis and interaction of cholinesterases with reversible and irreversible inhibitors. Kinetic parameters of hydrolysis of 18 esters, including choline, ammonium and indophenol derivates, are presented, as affected by cholinesterase from optical ganglia of pacific squid Todarodes pacificus, by acetylcholinesterase from human erythrocytes and by butyrylcholinesterase from horse serum. Some peculiarities of the squid cholinesterase are revealed, which are as follows: a low specificity at a rather high hydrolytic efficiency, the sensitivity towards inhibitory effects of several substrates at high concentrations. Reversible inhibition of the squid enzyme by ammonium inhibitors was dependent on the nature of substrates to a greater extent than that of the other enzymes. The substrate structure also conditioned various aspects of "the protective effect" in the course of irreversible inhibition of the squid cholinesterase by organophosphorous inhibitors.
这是首次将底物特异性视为一种复杂现象，同时考虑底物结构对酶促水解速率的影响以及胆碱酯酶与可逆和不可逆抑制剂的相互作用。文中给出了18种酯（包括胆碱、铵和吲哚酚衍生物）水解的动力学参数，这些参数受太平洋褶柔鱼（Todarodes pacificus）视神经节胆碱酯酶、人红细胞乙酰胆碱酯酶和马血清丁酰胆碱酯酶的影响。研究揭示了鱿鱼胆碱酯酶的一些特性，具体如下：在水解效率较高时特异性较低，对几种高浓度底物的抑制作用敏感。铵抑制剂对鱿鱼酶的可逆抑制在很大程度上比其他酶更依赖于底物的性质。底物结构还决定了有机磷抑制剂对鱿鱼胆碱酯酶不可逆抑制过程中“保护作用”的各个方面。
