Inhibition of protein kinase C activation by low concentrations of aluminium.

An extract of rat brain protein kinase C was fully activated at a total calcium concentration 3 x 10(-4) mol/l (Ca2+ 10(-4) mol/l) in the presence of non-limiting concentrations of phosphatidylserine. Available aluminium (ionised plus soluble hydrolysed) at a median value of 2 x 10(-8) mol/l inhibited enzyme activation by 90% at this non-limiting calcium concentration. Literature values for tissue aluminium concentrations suggest that interference with this key intracellular regulatory protein might occur in vivo.