Katrukha Ivan A, Riabkova Natalia S, Kogan Alexander E, Vylegzhanina Alexandra V, Mukharyamova Kadriya Sh, Bogomolova Agnessa P, Zabolotskii Artur I, Koshkina Ekaterina V, Bereznikova Anastasia V, Katrukha Alexey G
HyTest Ltd., Turku, Finland; Department of Biochemistry, School of Biology, Moscow State University, Moscow, Russia.
HyTest Ltd., Turku, Finland; Department of Biochemistry, School of Biology, Moscow State University, Moscow, Russia.
Clin Chim Acta. 2023 Mar 1;542:117281. doi: 10.1016/j.cca.2023.117281. Epub 2023 Mar 12.
Blood measurement of cardiac troponin T (cTnT) is one of the most widespread methods of acute myocardial infarction (MI) diagnosis. cTnT degradation may have a significant influence on the precision of cTnT immunodetection; however, there are no consistent data describing the level and sites of cTnT proteolysis in the blood of MI patients. In this study, we bordered major cTnT fragments and quantified their relative abundance in the blood at different times after MI.
Serial heparin plasma samples were collected from 37 MI patients 2-37 h following the onset of MI. cTnT and its fragments were studied by western blotting and immunofluorescence analysis using monoclonal antibodies specific to various cTnT epitopes.
cTnT was present in the blood of MI patients as 23 proteolytic fragments with an apparent molecular mass of ∼ 8-37 kDa. Two major sites of cTnT degradation were identified: between amino acid residues (aar) 68 and 69 and between aar 189 and 223. Analysis of the abundance of cTnT fragments showed an increase in the fraction of free central fragments in the first few hours after MI, while the fraction of the C-terminal fragments of cTnT remained almost unchanged.
cTnT progressively degrades after MI and appears in the blood as a mixture of 23 proteolytic fragments. The cTnT region approximately bordered by aar 69-158 is a promising target for antibodies used for measurement of total cTnT.
血液中心肌肌钙蛋白T（cTnT）的检测是急性心肌梗死（MI）诊断中应用最广泛的方法之一。cTnT的降解可能对cTnT免疫检测的准确性产生重大影响；然而，目前尚无一致的数据描述MI患者血液中cTnT蛋白水解的水平和位点。在本研究中，我们界定了主要的cTnT片段，并对MI后不同时间血液中它们的相对丰度进行了定量。
在MI发作后2 - 37小时从37例MI患者中采集系列肝素血浆样本。使用针对各种cTnT表位的单克隆抗体，通过蛋白质印迹法和免疫荧光分析研究cTnT及其片段。
MI患者血液中的cTnT以23种蛋白水解片段的形式存在，其表观分子量约为8 - 37 kDa。确定了cTnT降解的两个主要位点：氨基酸残基（aar）68和69之间以及aar 189和223之间。对cTnT片段丰度的分析表明，MI后最初几个小时内游离中央片段的比例增加，而cTnT C末端片段的比例几乎保持不变。
MI后cTnT逐渐降解，并以23种蛋白水解片段的混合物形式出现在血液中。aar 69 - 158大致界定的cTnT区域是用于测量总cTnT的抗体的一个有前景的靶点。
