FIG. 4.

Effects of NADA (■), ectoine (Ect) (▴), hydroxyectoine (Hect) (○), potassium DA (✠), and potassium chloride (⧫) on thermal inactivation of rabbit muscle LDH. (A) The enzyme was incubated at 50°C in the absence (●) or in the presence of one of the solutes, and samples were withdrawn at different times. (B) The enzyme was incubated at 50 or 55°C for 10 min in the presence or in the absence of one of the solutes. The activity of the enzyme was immediately assayed. Values are expressed as percentages of activity compared to the activity of the enzyme incubated at room temperature. All of the results are averages of the values from at least two independent experiments. The standard deviation was equal to or less than 10%.