Chemical and Immunological Comparisons of Allelic Immobilization Antigens in Paramecium aurelia

Abstract

PURIFIED immobilization antigens of Paramecium aurelia (syngen 1) were obtained from stocks containing different alleles at the D locus¹ and compared by the technique of ‘fingerprinting’^2,3. Previously^4,5 the antigen has been shown to be a protein of molecular weight approximately 250,000. It was extracted by the salt–alcohol method of Preer⁴ and purified by ammonium sulphate precipitation and chromatography on carboxy-methyl cellulose. Tryptic digests were prepared from antigen denatured by reduction with 2-mercaptoethanol, alkylated with iodoacetic acid⁶ and ‘fingerprinted’ by the method of Katz, Dreyer and Anfinsen³, except that the chromatographic solvent was n-butanol/water/acetic acid (17 : 9 : 4) and the electrophoresis buffer had a pH of 4.2.