The interaction of aluminium with soluble protein kinase C from mouse brain.

The interaction of aluminium ion species with soluble protein kinase C, Ca2+/phospholipid-dependent protein kinase, from mouse brain has been examined in vitro. The activity of protein kinase C was increased by addition of Ca2+ displaying an EC50 value of 10.3 +/- 1.1 x 10(-6) M. The A1 species inhibited the activity with an IC50 values of 8.6 +/- 0.5 x 10(-5) M and 2.7 +/- 0.3 x 10(-5) M in the presence of 0.5 mM Ca2+ and absence of Ca2+, respectively. Concerning the EC50 for Ca2+ activation, this was increased by the A1 species in a dose-dependent manner. Moreover, the inhibition was of a non-competitive type with respect to H1 histone and of a mixed type with respect to ATP. It is likely that the inhibition was caused by 1) the blocking of Mg2+ binding to ATP, 2) the blocking of CA2+ binding to protein kinase C. Our results suggested that protein kinase C was involved in neurotoxicity of A1.