Interaction of ruthenium red with Ca2(+)-binding proteins

Anal Biochem. 1990 Jul;188(1):123-31. doi: 10.1016/0003-2697(90)90539-l.


The interaction of ruthenium red, [(NH3)5Ru-O-Ru(NH3)4-O-Ru(NH3)5]Cl6.4H2O, with various Ca2(+)-binding proteins was studied. Ruthenium red inhibited Ca2+ binding to the sarcoplasmic reticulum protein, calsequestrin, immobilized on Sepharose 4B. Furthermore, ruthenium red bound to calsequestrin with high affinity (Kd = 0.7 microM; Bmax = 218 nmol/mg protein). The dye stained calsequestrin in sodium dodecyl sulfate-polyacrylamide gels or on nitrocellulose paper and was displaced by Ca2+ (Ki = 1.4 mM). The specificity of ruthenium red staining of several Ca2(+)-binding proteins was investigated by comparison with two other detection methods, 45Ca2+ autoradiography and the Stains-all reaction. Ruthenium red bound to the same proteins detected by the 45Ca2+ overlay technique. Ruthenium red stained both the erythrocyte Band 3 anion transporter and the Ca2(+)-ATPase of skeletal muscle sarcoplasmic reticulum. Ruthenium red also stained the EF hand conformation Ca2(+)-binding proteins, calmodulin, troponin C, and S-100. This inorganic dye provides a simple, rapid method for detecting various types of Ca2(+)-binding proteins following electrophoresis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism
  • Calcium Radioisotopes
  • Calcium-Binding Proteins / metabolism*
  • Calsequestrin / metabolism
  • Dogs
  • Electrophoresis, Polyacrylamide Gel
  • Erythrocytes / metabolism
  • Humans
  • Immunoblotting
  • Muscles / metabolism
  • Protein Binding / drug effects
  • Rabbits
  • Ruthenium Red / pharmacology*
  • Sarcoplasmic Reticulum / metabolism
  • Staining and Labeling


  • Calcium Radioisotopes
  • Calcium-Binding Proteins
  • Calsequestrin
  • Ruthenium Red
  • Calcium