[Comparison of the heat resistance of ATP-hydrolyzing enzymes in 2 species of frogs].

A comparison was made between the heat resistance levels of two enzymatic preparations: the actomyosinic and the transport ATPases of two species of frogs (grass and lake frogs) differing in their thermophilia. The interspecies differences in the heat resistance were found to be 6 degrees C for the actomyosinic and 3 degrees C for the transport ATPase in favour of the more thermophilic lake frog. In both species the myosinic ATPase is more sensitive to heat than the transport one. The high heat resistance of the transport ATPase is due to a higher threshold of its sensitivity to temperature.