Adaptation of enzymes to temperature: Myofibrillar adenosine tri-phosphatase from two terrestrial isopod species

Abstract

A comparison of the temperature profiles of the myofibrillar ATPase in Porcellio spinicornis and Metoponorthus pruinosus showed that Porcellio enzyme had a maximum activity between pH 6.8—7.2 at 9°C, and that from Metoponorthus between pH 7.0—7.4 at 45°C. The energy of activation for Porcellio enzyme was estimated to be 2.964 kcal/mol and that for Metoponorthus enzyme 9.91 10⁻¹ kcal/mol. The significance of these findings in relation to the natural habitats of these two species is discussed.