Mixed-function oxidase activity and conjugating enzymes in two species of Antarctic fish

Enzyme activities of phase I and phase II of the hepatic detoxication system were investigated in two species of fish from the Ross Sea in Antarctica. The fish had extremely low phase I enzyme (BPMO and aldrin epoxidase). The reductase regenerating enzyme activities were comparable to those found in fish of temperate seas. Transferases of cytosol showed highest activity in the conjugation of l-chloro-2.4-dinitrobenzene (CDNB) and little or no conjugation of other substrates. The GSSG reductase and the glutathione transferase with peroxidase activity (CuOOH substrate) were low; the Sedependent glutathione peroxidase activity was not detectable. Interspecific differences were found for most of the enzymes tested.