Lactic acid dehydrogenase

Lactic acid dehydrogenase (also known as LDH or lactate dehydrogenase) is an enzyme that is found in nearly all living cells. It catalyzes the conversion of lactate to pyruvate and back, as it converts NAD+ to NADH and back. This is an important process in cellular respiration.

Structure

LDH is a tetrameric enzyme that is made up of four subunits. These subunits can be of two types, M and H, which are encoded by two different genes, LDHA and LDHB. The different combinations of these subunits result in five different isoenzymes: LDH-1 (H4), LDH-2 (H3M1), LDH-3 (H2M2), LDH-4 (H1M3), and LDH-5 (M4).

Function

The main function of LDH is to catalyze the conversion of lactate to pyruvate, a critical step in the metabolic pathway that converts glucose into energy. This process also produces NADH, which is used in other metabolic processes.

Clinical significance

Elevated levels of LDH in the blood can be a sign of tissue damage, as the enzyme is released into the bloodstream when cells are damaged or destroyed. This can occur in a number of conditions, including heart attack, liver disease, and certain types of cancer. Therefore, measuring LDH levels can be useful in diagnosing and monitoring these conditions.

See also

• Lactate dehydrogenase deficiency
• Lactate dehydrogenase test

References

Lactic acid dehydrogenase Resources
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