Complex sentence: Mycobacterium tuberculosis has the enzyme pyrazinamidase which is only active at acidic pH. Pyrazinamidase converts pyrazinamide to the active form, pyrazinoic acid.
Split into simpler sentences: Mycobacterium tuberculosis has the enzyme pyrazinamidase. This enzyme is active at acidic pH. Pyrazinamidase converts pyrazinamide to the active form, pyrazinoic acid.