Catalyzes the cleavage of sphingomyelin, a major lipid in eukaryotic cells, into ceramide and phosphocholine, which are then utilized by M.bovis as carbon, nitrogen and phosphorus sources, respectively. Thus, enables M.bovis to utilize sphingomyelin as a source of several essential nutrients for intracellular growth during infection. Furthermore, lyses erythrocytes and constitutes a hemolytic factor. a sphingomyelin + H2O = an N-acylsphing-4-enine + H(+) + phosphocholine Consists of a surface-exposed C-terminal sphingomyelinase domain and a putative outer membrane-spanning N-terminal channel domain able to mediate glucose and phosphocholine uptake across the outer membrane. Belongs to the SpmT family.