Cardiac Troponin I, Myoglobin and Creatine Kinase MB are proteins released into the blood stream after cardiac injury. Cardiac Troponin I is a cardiac muscle protein with a molecular weight of 22.5 kilodalton.1 Troponin I is part of a three subunit complex comprising of Troponin T and Troponin C. Along with tropomyosin, this structural complex forms the main component that regulates the calcium sensitive ATPase activity of actomyosin in striated skeletal and cardiac muscle.2 After cardiac injury occurs, Troponin I is released into the blood 4-6 hours after the onset of pain.
