Which of the following pairs of tissues contain predominantly the LDH-5 (LDH-M4) isoenzyme?
- A Myocardium and erythrocytes
- B Liver and skeletal muscle ✓
- C Kidney and brain
- D Lung and platelets
Correct answer: B. Liver and skeletal muscle
Explanation
LDH-5 is composed of four M subunits and dominates in anaerobic glycolytic tissues such as liver and skeletal muscle, whereas LDH-1 (four H subunits) predominates in aerobic tissues like myocardium, erythrocytes, and renal cortex. This distribution explains the clinical pattern: LDH-1 predominance suggests myocardial injury or haemolysis, while a rising LDH-5 fraction indicates hepatocellular damage or extensive skeletal muscle injury.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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