[Effect of urea and heating on lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity].

Stability of lactatedehydrogenase (LDG) and glucose-6-phosphate dehydrogenase (G-6-PhDG) to the action of heating and urea on the muscle and on the enzymes isolated from muscle was studied. By the stability to the thermal agent in the system of the muscle and out of it LDG and G-6-PhDG exceed creatine kinase and aldolase; the most thermostable enzyme is G-6-PhDG. According to the action of urea on the muscle G-6-PhDG is the most stable enzyme, LDG is the most labile one among the studied enzymes. Under the action of urea on the isolated enzymes G-6-PhDG is the most labile one.