Lactate Dehydrogenase (LDH) ( 1 )

Lactose dehydrogenase (LDH) is an enzyme, present is all the cells of the body. It is a hydrogen transfer enzyme that catalyses the oxidation of lactate to pyruvate with nicotinamide-adenine dinucleotide (NAD)+ as hydrogen acceptor, the final step in the metabolic chain of anaerobic glycolysis. The reaction is reversible and the reaction equilibrium strongly favors reverse reaction, namely the reduction of pyruvate to lactate. The tissue levels of this enzyme is 500 fold higher than those normally present in serum.

Thus, any cell or tissue damage elevates the serum level of LDH to a significant extent. Thus, the increased level of LDH in blood is generally an indication of cellular damage.