Table 1: Stability of rat brain AChE activity.

S. numberDays% AChE activity remaining

10100
27100
31499.8
42199.8
52899.5
63099.5

Effect of storage time at −20°C on the activity of AChE from human erythrocytes was observed by carrying out the enzyme assay employing 50 µg protein on different days as described in Materials and Methods. The enzyme was stored in phosphate buffer (50 mM, pH 7.4) containing 0.2% Triton X-100.