Table VII.

Heat stability of purified maize AGPase and the small-subunit mosaics^a

Enzyme	t1/2 42°C	t1/2 55°C
	min	min
Maize AGPase	4.5	0.35
MPss/Mls	18	1.4
P2M2Pss/Mls	>180	27.4
Pss/Mls	>180	19.3

^aAssays were performed using assay B (forward direction). Each enzyme was desalted into 50 mm HEPES, pH 7.4, 5 mm MgCl₂, 0.5 mm EDTA at a protein concentration of 0.01 mg/mL, followed by the addition of BSA (0.5 mg/mL). Data were plotted as log % activity versus time, and the inactivation constant t_1/2 was calculated from the slope of the straight line.