Selective staining procedures for four different enzymes (malate dehydrogenase, glutamic oxaloacetic transaminase, leucine aminopeptidase and glucose phosphate isomerase) in combination with two-dimensional immunoelectrophoresis were successfully applied to the analysis of antigen preparations from mycobacteria. Thus, a precipitate corresponding to malate dehydrogenase could e.g. be demonstrated in multi-linear precipitation patterns of Mycobacterium avium, Mycobacterium bovis BCG, Mycobacterium intracellulare, Mycobacterium kansasii, Mycobacterium marinum and Mycobacterium phlei. The analytical approach described can be advantageously used for identification of mycobacterial precipitinogens of enzyme character.