In analogy to glutathione, mycothiol is part of the detoxification machinery of the M. tuberculosis cell. The biotransformation of electrophilic toxins consists of creating an adduct with mycothiol, its cleavage into a "mercapturic acid" and glucosaminyl-inositol (with which mycothiol is recycled), and transport of the mercapturic acid through the membrane. The protein(s) catalyzing the transport are still unidentified.

Further molecules that are changed to less dangerous entities with the help of mycothiol are formaldehyde and the nitrosyl radical (Rawat and Av-Gay, 2007; Newton et al, 2008).