3.3.2. SapM Inhibitors

Another virulence factor that affects phagocytosis and phagosome formation is the secreted acid phosphatase M (SapM) (Figure 1). SapM shows activity as a monoester alkaline phosphatase and targets two phosphoinositides (PI(4,5)P2 and PI3P) important for phagosome maturation [115]. In inhibition studies, it was shown that 2-phospho-L-ascorbic acid interferes with SapM activity without attenuating extracellular bacterial growth. At 4 mM, this drug could reduce intracellular growth of *M. tuberculosis* by 39% [116].
