scholarly journals Degradation of cardiac troponin I: implication for reliable immunodetection

1998 ◽  
Vol 44 (12) ◽  
pp. 2433-2440 ◽  
Author(s):  
Aleksei G Katrukha ◽  
Anastasia V Bereznikova ◽  
Vladimir L Filatov ◽  
Tatiana V Esakova ◽  
Olga V Kolosova ◽  
...  
Keyword(s):  
Cardiac Troponin ◽  
Troponin I ◽  
Cardiac Troponin I ◽  
Immunological Methods ◽  
Proteolytic Degradation ◽  
Necrotic Tissue

Abstract We have analyzed by different immunological methods the proteolytic degradation of cardiac troponin I (cTnI) in human necrotic tissue and in serum. cTnI is susceptible to proteolysis, and its degradation leads to the appearance of a wide diversity of proteolytic peptides with different stabilities. N- and C-terminal regions were rapidly cleaved by proteases, whereas the fragment located between residues 30 and 110 demonstrated substantially higher stability, possibly because of its protection by TnC. We conclude that antibodies selected for cTnI sandwich immunoassays should preferentially recognize epitopes located in the region resistant to proteolysis. Such an approach can be helpful for a much needed standardization of cTnI immunoassays and can improve the sensitivity and reproducibility of cTnI assays.

scholarly journals Proteolytic Digestion of Serum Cardiac Troponin I as Marker of Ischemic Severity

2018 ◽  
Vol 3 (3) ◽  
pp. 450-455 ◽  
Author(s):  
Somaya Zahran ◽  
Vivian P Figueiredo ◽  
Michelle M Graham ◽  
Richard Schulz ◽  
Peter M Hwang
Keyword(s):  
Cardiac Troponin ◽  
Troponin I ◽  
Thrombus Formation ◽  
Cardiac Troponin I ◽  
Total Serum ◽  
Proteolytic Degradation ◽  
Troponin Level ◽  
Proteolytic Digestion ◽  
Severity Of Injury ◽  
Clinically Significant

Abstract Background The serum troponin assay is the biochemical gold standard for detecting myocardial infarction (MI). A major diagnostic issue is that some believe troponin levels can rise with reversible injury, in the absence of radiologically detectable infarct. Hypothesis Because cell death activates intracellular proteases, troponin released by irreversible infarct will be more proteolyzed than that released by milder processes. Our goal was to quantify proteolytic digestion of cardiac troponin I in patients with varying degrees of myocardial injury. Methods Serum or plasma samples from 29 patients with cardiac troponin I elevations were analyzed for proteolytic degradation, using 3 different sandwich ELISAs designed to specifically detect the N-terminal, core, or C-terminal regions of cardiac troponin I. Results As predicted, the degree of proteolytic digestion increased with increasing severity of injury, as estimated by the total troponin level, and this trend was more pronounced for C-terminal (vs N-terminal) degradation. The highest degree of proteolytic digestion was observed in patients with ST-elevation MI; the least, in type 2 MI (supply–demand ischemia rather than acute thrombus formation). Conclusions The proteolytic degradation pattern of cardiac troponin I may be a better indicator of clinically significant MI than total serum troponin level. Distinguishing between intact and degraded forms of troponin may be useful for (a) identifying those patients with clinically significant infarct in need of revascularization, (b) monitoring intracellular proteolysis as a possible target for therapeutic intervention, and (c) providing an impetus for standardizing the epitopes used in the troponin I assay.

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