the inhibition of na ( + ) -plus-k ( + ) -activated adenosine triphosphatase of cell membranes by low concentrations of caatp and the consequent need of intact cells to keep the cytoplasmic concentration of calcium low relative to that of magnesium suggests a raison d'etre for the mitochondrial calcium pump .
C0007603
cell membranes
C0010834
cytoplasmic