LDH 5 is seen in ?
## **Core Concept**
LDH 5, also known as lactate dehydrogenase 5 (LDH-5), is an isoenzyme of lactate dehydrogenase. LDH is a crucial enzyme in glucose metabolism, facilitating the interconversion of lactate and pyruvate. LDH exists in five isoforms (LDH 1 to LDH 5), which are tetramers composed of different combinations of two subunits, H (heart) and M (muscle).
## **Why the Correct Answer is Right**
LDH 5 is predominantly found in skeletal muscle and the liver. It has a high affinity for pyruvate and plays a significant role in anaerobic glycolysis, producing lactate from pyruvate. This isoenzyme is particularly abundant in tissues that rely heavily on anaerobic metabolism, such as skeletal muscle. Therefore, LDH 5 is associated with **skeletal muscle**.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because LDH 1 is predominantly found in the heart, not LDH 5.
- **Option B:** This option might seem plausible but is incorrect because while LDH 5 is indeed found in the liver, the question seems to be pointing towards a more specific tissue association.
- **Option C:** This option is incorrect because it does not accurately represent the primary location of LDH 5.
## **Clinical Pearl / High-Yield Fact**
A key clinical correlation is that elevated LDH 5 levels can be seen in conditions associated with increased skeletal muscle damage or high rates of anaerobic glycolysis, such as intense exercise or certain muscular dystrophies. LDH 5 is also implicated in cancer progression, particularly in tumors with high rates of glycolysis.
## **Correct Answer:** . Skeletal muscle