laktaatdehüdrogenaas

Laktaatdehüdrogenaas, often abbreviated as LDH or LD, is an enzyme that plays a crucial role in cellular respiration. It is found in nearly all tissues of the body, with particularly high concentrations in the muscles, heart, liver, kidneys, and red blood cells. The primary function of LDH is to catalyze the interconversion of lactate and pyruvate. This reaction is a key step in both aerobic and anaerobic metabolism.

Under aerobic conditions, where oxygen is present, pyruvate is typically converted into acetyl-CoA and enters the Krebs cycle for energy production. However, when oxygen supply is limited, such as during intense physical activity, pyruvate is converted to lactate by LDH. This process regenerates NAD+, which is essential for glycolysis to continue producing ATP. Lactate can then be transported to other tissues, like the liver, where it can be converted back to pyruvate and used for energy or glucose synthesis.

The presence of LDH in the bloodstream is a common indicator in medical diagnostics. Elevated levels of LDH in serum can suggest tissue damage or cell lysis, as the enzyme is released from damaged cells into the circulation. It is therefore a non-specific marker for a wide range of conditions, including heart attack, muscle injury, liver disease, certain cancers, and hemolytic anemia. Measuring different isoenzymes of LDH (LD1-LD5), which are variations of the enzyme found in different tissues, can help pinpoint the source of the elevated levels.