Figure 8.

Biphasic nature of heat inactivation. A, AGPase (0.02 mg/mL) was mixed to a final concentration of 10 mm phosphate and incubated on ice for 5 min. Enzymes were then heated at 45°C for the specified amount of time and placed back on ice. When all of the time points were completed, the enzymes were assayed using standard protocols. B, AGPase was prepared as above and assayed in the reverse direction. C, Enzymes were prepared as in A. The entire mixture was then heated at 45°C for 7 min and then cooled on ice. The same experiment was then performed as in A. D, No phosphate was added to the enzyme. Heat treatment was performed at 37°C.