FIGURE 3.

Activation of apo-α₂β₂ by apo-αe₂ under various conditions in vitro. A, effect of the DTT concentration on apo-α₂β₂ activation. Apo-α₂β₂ was mixed with apo-αe₂ in the activation buffer containing 20 μm CoCl₂ and 0, 0.5, 1, 2, 4, 6, 8 or 10 mm DTT. B, effect of the cobalt concentration on apo-α₂β₂ activation. Apo-α₂β₂ was mixed with apo-αe₂ in the activation buffer containing 2 mm DTT and 0, 5, 10, 20, 40, 60, or 80 μm CoCl₂. Aliquots of the samples were removed at 12 h and then assayed for L-NHase activity. Values represent the means ± S.D. for at least triplicate independent experiments.