Enzymes of Antarctic fishes: effect of temperature on catalysis ...

• Main Authors: Ciardiello, Maria Antonietta, Camardella, Laura, Di Prisco, Guido
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Société Française d'Ichtyologie 1997
• Subjects: Antarctic Ocean, Channichthyidae, Enzyme, Nototheniidae, PSE, Temperature effect; Antarctic; Antarctic Ocean; The Antarctic; Antarc*
• Online Access: https://dx.doi.org/10.26028/cybium/1997-214-011; https://sfi-cybium.fr/fr/enzymes-antarctic-fishes-effect-temperature-catalysis

We have investigated the temperature effect on the catalytic activity of three enzymes from Antarctic fish: glucose-6-phosphate dehydrogenase (G6PD) from the blood of the white-blooded channichthyid Chionodraco hamatus and the red-blooded nototheniid Dissostichus mawsoni, L-glutamate dehydrogenase (GDH) from the liver of the channichthyid Chaenocephalus aceratus and glycogen phos-phorylase b from the muscle of the nototheniid Trematomus bernacchii. The study of the temperature effect on the catalytic activity of G6PD and GDH shows that the Antarctic enzymes are more efficient catalysts at low temperature than the mesophilic homologous enzymes. The activity of Antarctic G6PD increases at increasing temperatures; above 55°C irreversible heat inactivation occurs. A different beha-vior is shown by C. aceratus GDH. This enzyme has an apparent optimal temperature at 25°C; above this temperature, the catalytic activity decreases and irreversible heat inactivation is then observed above 45°C. All three enzymes are ...