Cardiac troponin T degradation in serum is catalysed by human thrombin

Area of Science:

• Biochemistry
• Cardiology
• Proteomics

Background:

• Cardiac troponin T (cTnT) fragmentation occurs in human serum post-acute myocardial infarction (AMI).
• Intracellular proteases like calpain-1 and caspase-3 cleave cTnT's N-terminus, but serum proteases responsible for extensive fragmentation remain unidentified.

Purpose of the Study:

• To investigate the potential role of human thrombin in the extensive fragmentation of cTnT observed in AMI patient serum.

Main Methods:

• Purified human cTnT was incubated with processed and unprocessed human serum.
• Experiments involved the addition of purified human thrombin or a thrombin inhibitor (PPACK).
• Techniques included immunoprecipitation, SDS-PAGE, and Western blotting to analyze cTnT fragmentation.

Main Results:

• Addition of purified thrombin to deproteinated serum increased cTnT fragmentation.
• Inhibition of thrombin in unprocessed serum reduced cTnT fragmentation.
• These findings indicate thrombin's involvement in cTnT degradation.

Conclusions:

• Multiple enzymes contribute to cTnT degradation in serum after AMI.
• Human thrombin plays a significant role in the progressive fragmentation of cTnT.