Zorko M, Pavlic M R
Biochem Pharmacol. 1986 Jul 15;35(14):2287-96. doi: 10.1016/0006-2952(86)90453-3.
The binding of D-tubocurarine (TC) to acetylcholinesterase (AChE) was studied using different methods of enzyme kinetics. The main results are as follows. TC reversibly inhibits the hydrolysis of different substrates of AChE with three different inhibition constants (Ki1 = 7.0 +/- 0.8 X 10(-5) M, Ki2 = 3.1 +/- 1.0 X 10(-4) M, and Ki3 = 4.2 +/- 0.5 X 10(-3) M). Reference inhibitors tetramethylammonium (TMA), tetraethylammonium (TEA), and decamethonium (C-10) inhibit the hydrolysis of different substrates with constants, which are the same for each individual inhibitor. These three inhibitors compete with TC in the inhibition of enzymatic hydrolysis of acetylthiocholine (ASCh); all three of them affect the noncompetitive component of the inhibition of the hydrolysis of ASCh by TC, which arises from the binding of TC to the peripheral anionic site of AChE, but TEA and C-10 affect also the competitive component of this inhibition, which arises from the binding of TC at the catalytic anionic site. TC partially inhibits the methanesulfonylation of AChE; dissociation constant for TC in this process is KA = 4.5 X 10(-4) M. All our results lead to the conclusion that TC binds to three regions on the active surface of AChE. The first region is at the peripheral anionic site; the other two regions are situated in the vicinity of the catalytic anionic site and the esteratic site.
使用不同的酶动力学方法研究了D - 筒箭毒碱（TC）与乙酰胆碱酯酶（AChE）的结合。主要结果如下。TC以三种不同的抑制常数可逆地抑制AChE不同底物的水解（Ki1 = 7.0 +/- 0.8×10^(-5) M，Ki2 = 3.1 +/- 1.0×10^(-4) M，Ki3 = 4.2 +/- 0.5×10^(-3) M）。参考抑制剂四甲基铵（TMA）、四乙铵（TEA）和十烃季铵（C - 10）以对每种单独抑制剂而言相同的常数抑制不同底物的水解。这三种抑制剂在抑制乙酰硫代胆碱（ASCh）的酶促水解方面与TC竞争；它们都影响TC对ASCh水解抑制的非竞争性成分，这是由TC与AChE外周阴离子位点的结合引起的，但TEA和C - 10也影响这种抑制的竞争性成分，这是由TC在催化阴离子位点的结合引起的。TC部分抑制AChE的甲磺酰化；在此过程中TC的解离常数为KA = 4.5×10^(-4) M。我们所有的结果得出结论，TC与AChE活性表面的三个区域结合。第一个区域在外周阴离子位点；另外两个区域位于催化阴离子位点和酯酶位点附近。
