Purification and Characterization of Two Proteins from Culture Filtrates of Mycobacterium tuberculosis H 37 Ra Strain

Abstract
Two proteins have been purified from culture filtrates of Mycobacterium tuberculosis, H37Ra strain by a procedure combining gel filtration, diethylaminoethyl (DEAE)-cellulose chromatography, and zone electrophoresis. The two proteins are similar in molecular weight but differ slightly in charge. The faster migrating protein, designated a1, is not antigenic. The slower migrating protein, designated a2, is antigenic both with respect to antisera and as a skin-testing antigen.