魚体のカタラーゼについて-I

Abstract

1) Thermostability of catalase of liver extracts of poecilothermic animals namely five kinds of fresh-water fishes (cold water fishes: rain-bow trout and Oncorhynchus formosunus; semicold water fish: Plecoglossus altivelis; warm-water fishes: carp and crucian) was constrasted with that of homoesthermic animal, domestic fowl. 2) Stability of catalase of liver extracts in relation to temperature was found to vary considerably with species of the animals studied, and to stand in close relation with temperatures suited for leading their life. 3) Liver catalase of the cold-water fishes was stable at 20°C but inactivated slowly at 30°C and rapidly at 40°C. 4) The same of the semi-cold water fish, Plecoglossus altivelis, was stable at 30°C but inactivated slowly at 40°C and rapidly at 45°C. 5) On the other hand, a slight augmentation of activity of the warm water fishes was observed at 25°C and a much remarkable one at 30°-40°C, but followed by inactivation after 30-60 minutes' exposure. A rapid inactivation of it was evident from the start when experimented at 45°C. 6) Liver-extract of the domestic fowl was found continuously increasing it activity at 30°-40°C. Rapid activation of it took place at 45°-55°C but gradual inactivation appeared at heels after 60 minutes' lapse of time. Neither augmentation nor decrease in activity of the enzyme in question was observed at 60°C. 7) Liver catalase is extremely stable at temperatures wich are either optima for living or ordinary body temperatures of animals. But heating beyond the ranges tends to cause slow or rapid inactivation. Sometimes such treatment leads to appearent activation of the enzyme at first but it is bound to end in opposite direction. 8) Energies of inactivation are shown in Table 2.