M. tuberculosis H37Ra possesses two l-asparaginases while the H37Rv strain possesses only a single enzyme. These enzymes have been purified and their properties studied. The two l-asparaginases in H37Ra strain differ from each other in pH optima, heat inactivation, Michaelis constant and effects of inhibitors, while one of them resembles the single l-asparaginase present in the H37Rv strain. l-Cysteine inhibits both l-asparaginases in an allosteric manner probably because it is one of the end-products in l-asparagine metabolism. This is the first time that a qualitative difference has been reported in the enzyme pattern between the avirulent and virulent strains of M. tuberculosis.
ASJC Scopus subject areas
- Molecular Biology