Degradation of cardiac troponin I: implication for reliable immunodetection.
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.
Katrukha
A G
AG
1 HyTest LTD, Tykistokatu 6A, FIN-20520 Turku, Finland.
Bereznikova
A V
AV
Filatov
V L
VL
Esakova
T V
TV
Kolosova
O V
OV
Pettersson
K
K
Lövgren
T
T
Bulargina
T V
TV
Trifonov
I R
IR
Gratsiansky
N A
NA
Pulkki
K
K
Voipio-Pulkki
L M
LM
Gusev
N B
NB
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D010450:Endopeptidases / Q000378:metabolism; D000939:Epitopes; D015200:Fluoroimmunoassay; D006801:Humans; D006868:Hydrolysis; D008969:Molecular Sequence Data; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D010446:Peptide Fragments / Q000032:analysis* / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D020107:Troponin T / Q000032:analysis / Q000276:immunology / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D010446:Peptide Fragments; D020107:Troponin T; D010450:Endopeptidases