The nuoG gene of Mycobacterium tuberculosis (Mtb) has the ability to inhibit host cell apoptosis. This ability is a virulence factor and does not exist in facultative pathogenic and non-pathogenic mycobacterial species. NuoG is part of the NDH-1 complex, and this study addressed the potential link between the role of NuoG in apoptosis inhibition and the biochemical activity of the NDH-1 complex. Different mycobacterial species were tested for their NDH-1 activities. Among the bacteria tested were bacteria transformed with the Mtb nuoG plasmid, or with the almost entire NDH-1 coding region. Surprisingly, the levels of NDH-1 activity did not correlate with apoptosis levels, suggesting a potential independent, novel mechanism by which NuoG inhibits host cell apoptosis.