troponíni

Troponins are a group of proteins found in cardiac and skeletal muscle. They play a crucial role in muscle contraction by regulating the interaction between actin and myosin filaments. The troponin complex consists of three distinct subunits: troponin C (TnC), troponin I (TnI), and troponin T (TnT). Troponin C binds to calcium ions, which triggers a conformational change in the complex. This change allows tropomyosin to move away from the actin binding sites, permitting myosin to bind and initiate the contractile process. Troponin I inhibits the interaction between actin and myosin in the absence of calcium, while troponin T binds to tropomyosin, anchoring the troponin complex to the thin filament.

In clinical medicine, cardiac troponins (specifically troponin I and troponin T) are highly significant biomarkers. When heart muscle is damaged, such as during a myocardial infarction (heart attack), these proteins are released into the bloodstream. The measurement of cardiac troponin levels in blood is a sensitive and specific diagnostic tool for detecting myocardial injury. Elevated troponin levels can indicate even minor damage to the heart muscle and are often used to confirm a diagnosis of a heart attack, guide treatment decisions, and monitor the effectiveness of therapy. Their presence in the blood typically rises within a few hours of muscle damage and can remain elevated for several days.