PROTEIN-TYROSINE PHOSPHORYLATION IN MYCOBACTERIUM-TUBERCULOSIS

Crude cell extracts from three strains of Mycobacterium tuberculosis w ere analyzed for the presence of proteins possessing phosphorylated ty rosine residues. A protein migrating at approximately 55 kDa was detec ted using an antiphosphotyrosine monoclonal antibody. In addition, les s predominant bands were observed between 50 kDa and 60 kDa. That M. t uberculosis contains specific tyrosine phosphorylated proteins implies that M. tuberculosis has tyrosine kinase activity. Examination of oth er, non-pathogenic mycobacterium species yielded no major antiphosphot yrosine reactive proteins. This suggests that the antiphosphotyrosine reactive protein is specific to M. tuberculosis strains. These results provide evidence that M. tuberculosis contains an antiphosphotyrosine reactive protein.