Inhibition of Mg, Ca-ATPase from E. coli by ruthenium red

The membrane-bound, solubilized, and trypsin-treated forms of Mg, Ca-ATPase from E. coli are inhibited by ruthenium red [RR]. The inhibition is noncompetitive and is reduced at higher substrate concentrations. n-Butanol-extracted ATPase is not inhibited by ruthenium red and is not activated by KCl.