Figure 3.

Inorganic Pyrophosphatase Activity in Fibroblast Mitochondria and Recombinant Enzymes

(A and B) Activity of inorganic pyrophosphatase in different fibroblast mitochondria isolations from affected individuals (P) P5, P7, and P9 compared to 14 control subjects (C) at different PPi concentrations and either (A) 0.5 mmol/L MgCl₂ or (B) 3.0 mmol/L MgCl₂.

(C) Inhibition of inorganic pyrophosphatase in fibroblast mitochondria from affected individual P5 (red squares) and three control subjects (black circles) incubated at 0.5 mmol/L MgCl₂ and different CaCl₂ concentrations and either 0.1 mmol/L PPi or 0.01 mmol/L PPi (small insert).

(D) Pyrophosphatase activity of equal amounts of recombinant proteins at different PPi concentrations.

(E) Protein amount of recombinant PPA2 protein was adjusted by western blot analysis and silver staining (Figure S9).

^∗p < 0.01, ^∗∗p < 0.0001 in Student’s unpaired t test. The error bars in this graph indicate the standard error of the mean.