67Ga binding to human serum proteins and tumor components.

radionuclide is associated with transferrin, apart from a weak binding to 0-lipoprotein. The thermodynamic con stant for gallium was estimated and indicated that gallium citrate in the presence of serum proteins occurred in a colloid form bound to transferrin. Ultracentrifugation of tumor homogenates obtained from patients who had received i.v. injections of 67Ga citrate for scintigraphy demonstrated that 67Ga is preferentially bound to proteins in the nuclei fraction. Acrylamide gel electrophoresis of extracts of cancer tissue indicated that intracellular 67Ga is associated mainly with a fast-migrating