1.8.4.2 dimerization after prolonged storage at -20°C, freeze-thawing or heating at 60°C 394836 1.8.4.2 EDTA 5mM, 37°C, phosphate buffer, total loss of activity within 30-60 min, can partially be prevented by NADPH 394815 1.8.4.2 EDTA stabilizes during purification 394820, 394848 1.8.4.2 GSH, 10 mM, enhances heat stability 394848 1.8.4.2 highly susceptible to proteolytic attack 394844 1.8.4.2 insulin, 0.087 mM, decreases heat stability 394848 1.8.4.2 metal ions required for activity and maintenance of the proper conformation of the enzyme 394815