Page 124 - Practical Handout bio 2 mnu 2025_Neat
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Level two – Semester 4 - PharmD Biochemistry-II PB-403 (Practical course) 2024/2025
1. Myoglobin
Myoglobin is a low-molecular-weight protein present in all
skeletal and cardiac muscle.
Due to its small size, it appears in serum rapidly after release
from injured muscle and is cleared into the urine.
It is the least specific of any of the cardiac markers due to its
presence in all muscles.
2. Creatine kinase (CK):
Creatine kinase (CK) is an enzyme responsible for the conversion of
creatine into phosphocreatine, the energy source for muscle
contraction.
Total CK is composed of 3 iso-enzymes in blood:
CK-MM (CK-1) CK- MB (CK-2) CK-BB (CK-3)
Myocardial and
Skeletal Muscle Brain
skeletal muscle
3. Troponin:
❖ Troponin is a regulatory protein complex of three proteins on
the thin filaments of skeletal and cardiac muscle fibers.
❖ During muscle contraction, the troponin complex regulates the
interaction between the thick and thin filaments.
This complex consists of:
Troponin T Troponin I Troponin C
The amino acid sequences of TnT and TnI
Identical in skeletal
found in cardiac muscle are different from
and cardiac muscle
those of the troponins in skeletal muscle.
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