In this study, the properties and gene expression of the lactate dehydrogenase (EC 1.1.1.27, LDH) isozyme were studied in angelfish (Pterophyllum scalare) -known for their adaptation to the low oxygen environment of the tropicswhich were acclimated to acute temperature change (27±0.5→18±0.5℃) and dissolved oxygen (DO) change (6±1→18 ppm) for 2 hours. The properties of the LDH isozymes were confirmed in the native-polyacrylamide gel electrophoresis, Western blot analysis and enzyme activity

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... rement. Liver-and eye-specific Ldh-C gene were expressed in liver, eye and brain tissues. Through Western blot analysis, the LDH A4 isozyme was shown to have a more cathodal mobility relative to the B4 isozyme. In the liver tissue, the LDH A4 isozyme increased with temperature drop while the B4 isozyme decreased. The LDH A4 and C4 isozymes increased with DO increment, while the B4 isozyme decreased. In the eye tissue, the LDH A4 and B4 isozymse increased with temperature drop while the C4 isozyme decreased. The LDH A4 and B4 isozymes increased with DO increment, but the C4 isozyme and isozymes including the subunit C decreased. In the heart tissue, LDH activity increased with DO increment, as well as the LDH B4 isozyme. In the brain tissue, the LDH A4 and B4 isozymes increased with temperature drop. The LDH B4 isozyme increased with DO increment. Accordingly, since the liver-and eye-specific Ldh-C are influenced by changes in DO and the LDH B4 and C4 isozymes are relatively controlled in the liver and eye tissues, the C4 isozyme can be considered to have a lactate oxidase function.