Sodium salicylate for fluorographical detection of immunoprecipitated proteins in agarose gels

Abstract

AbstractFilm detection of compounds labeled with the weak beta‐emitters 3H and 14C is demonstrated for electroimmunoprecipitated proteins in agarose gels by means of the water‐soluble fluorophor sodium salicylate. The degree of enhancement of film detection of tritium and carbon‐14 with 0.7 M sodium salicylate paralleled fluorography with diphenyloxazole on polyacrylamide gels. The method was optimized and the sensitivity, expressed as radioactivity per cm immunoprecipitate, was 0.9 nCi/cm (2000 dpm/cm) in 24 h for 3H and 0.4 nCi/cm (830 dpm/cm) in 18 h for 14C. The procedure was found superior to the commercially available enhancement solutions ‘EnHance’ and ‘Amplify’. Salicylate fluorography on Kodak X‐Omat L and AR‐5 films was about 30 and 60 times more sensitive than Ultrofilm 3H. With 14C‐labeled anti‐antibodies rocket electroimmunoprecipitation corresponding to about 50–100 pg protein could be visualized in 7 days. Conclusively, the method is rapid (soaking and drying require about 30 min), sensitive, reproducible, cheap, and advantageous if the immunoplates are to be stained for protein after fluorography.