Petushkova E V, Risnik V M, Sokolova N I, Tret'iakova S S, Shabarova Z A
Biokhimiia. 1980 Apr;45(4):726-32.
Mixed anhydrids of AMP, ADP, ATP and IMP and mesitylene carboxylic acid (AMP-MC, ADP-MC, ATP-MC and IMP-MC) are efficient irreversible inhibitors of the Ca-ATPase activity of myosin and heavy meromyosin. The highest rate of inhibition is observed in the case of AMP-MC: at AMP-MC concentration of 1,5.10(-3) M the half inactivation time for heavy meromyosin varies in different protein preparations from 10 to 20 min. The rates of inhibition in the presence of ADP-MC and ATP-MC are roughly the same and are far lower than those for AMP-MC (half inactivation time is 1,5-2 hrs). However, in the latter case the inhibition is complete, the time of the analogs interaction with the protein being increased up to several hours. In the presence of IMP-MC the inhibition is also time-dependent but is never complete. A necessary condition for the manifestation of irreversible inhibition of the Ca-ATPase activity of TMM by phosphorylating analogs of the substrate is the presence of bivalent cations. No inhibition occurs in the presence of EDTA. An addition of ADP or ATP to the preincubation medium causes a sharp decrease of the inhibition rate (a protective effect), which suggests a specific interaction of the analogs with TMM at the substrate binding site.
AMP、ADP、ATP和IMP与均三甲苯羧酸的混合酸酐（AMP-MC、ADP-MC、ATP-MC和IMP-MC）是肌球蛋白和重酶解肌球蛋白Ca-ATP酶活性的有效不可逆抑制剂。在AMP-MC的情况下观察到最高抑制率：在AMP-MC浓度为1.5×10⁻³ M时，重酶解肌球蛋白的半失活时间在不同蛋白质制剂中为10至20分钟。在ADP-MC和ATP-MC存在下的抑制率大致相同，远低于AMP-MC的抑制率（半失活时间为1.5至2小时）。然而，在后一种情况下抑制是完全的，类似物与蛋白质的相互作用时间增加到数小时。在IMP-MC存在下，抑制也是时间依赖性的，但从未完全抑制。通过底物的磷酸化类似物对TMM的Ca-ATP酶活性进行不可逆抑制表现的一个必要条件是二价阳离子的存在。在EDTA存在下不发生抑制。向预孵育培养基中添加ADP或ATP会导致抑制率急剧下降（保护作用），这表明类似物与底物结合位点处的TMM发生特异性相互作用。
