Serological, Taxonomic, and Kinetic Studies of the T and M Classes of Mycobacterial Catalase

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Abstract
Two types of catalase may be found in extracts of mycobacteria, the heat-labile T class and the heat-stable M class. The T-catalase is resistant to 3-amino-1,2,4-triazole and has a Km in the range of 3.1-6.8 mM H2O2, whereas the M-catalase is inhibited by 3-amino-1,2,4-triazole and has a Km in the range of 143-156 mM. Some species of mycobacteria produce only 1 class of catalase and others produce both. Of the species studied, only Mycobacterium terrae, M. triviale and M. nonchromogenicum failed to exhibit T-catalase, although all 3 of these species had M-catalase. M. tuberculosis, M. bovis, M. intracellulare, M. avium, M. gastri, M. marinum and M. xenopi yielded T-catalase but not M-catalase. Six species, M. szulgai, M. simiae, M. kansasii, M. gordonae, M. scrofulaceum and M. asiaticum, produced both classes. The differences in resistance to heat and 3-amino-1,2,4-triazole were exploited in the development of methods for quantitative serological characterization of 1 class of catalase in the presence of the other. These techniques were used with 3 reference sera to produce a branching diagram of divergence of the T-catalases from 13 species of mycobacteria based on measurements of immunological distance. No T-catalase could be demonstrated in another 3 species. A first-stage study was also carried out with a single reference antiserum to M-catalase from M. kansasii. Representatives of 9 mycobacterial species, including the 3 that produced no T-catalase, were characterized with this reference system, which tends to yield larger immunological distance values than the T-catalase system.