In order to examine the surface structure of cancer cells, ascites hepatoma cells (AH-130) were treated with ruthenium red known to interact readily with certain acidic carbohydrates. This treatment induces specific cell agglutination, which has been shown to depend upon the cell surface acidic mucopolysaccharide and glycoprotein. In the present study, an attempt was made to isolate the ruthenium red-binding glycoprotein and to examine its biochemical properties and biological characteristics.
Ruthenium red-binding glycoprotein was solubilised by treating AH-130 ascites hepatoma cells with a low concentration of papain, then fractionated by Sephadex G-200. This glycoprotein eluted as the fastest band on gel electrophoresis (glycine buffer pH 7.8) and showed a positive reaction for metachromatic toluidine blue. This fraction was isolated. The purified glycoprotein had a molecular weight a little higher than that of bovine serum albumin. There was a high content of acidic amino acid similar to that of Ca(++)-binding proteins described by other investigators. A considerable amount of galactose, hexosamine and sialic acid was also present. The glycoprotein bound strongly to ruthenium red. Ruthenium red inhibited PHA-induced blastoid transformation of lymphocytes and increased the endogenous respiratory activity of AH-130 ascites hepatoma cells. It was concluded that the ruthenium redbinding glycoprotein on the cell surface was related to the metabolic regulation of cells and to the metabolic disorder of cancer cells.