Serum lactate dehydrogenase isoenzyme

The lactate dehydrogenase (LDH) in human tissues can be separated into five isozyme bands by electrophoresis. According to the speed of their electrophoretic mobility, they are named LDH1, LDH2, LDH3, LDH4, and LDH5. The distribution of lactate dehydrogenase isoenzymes in different tissues is different, with obvious tissue specificity. LDH1 and LDH2 are the most in human heart, kidney and red blood cells, LDH4 and LDH5 are the most in skeletal muscle and liver, and lung, spleen, pancreas , Thyroid, adrenal gland and lymph node tissues are the most LDH3. LDHx was later found in testes and sperm, and its electrophoretic mobility was between LDH4 and LDH5. LDH is composed of two types of subunits: H (myocardial type) and M (skeletal muscle type), which form LDH1 (H4), LDH2 (H3M), LDH3 (H2M2), LDH4 (HM3), and LDH5 (M4).