Mertansine is a tubulin inhibitor，inhibits the assemblyof microtubules by binding to tubulin,  with a linker structure can create an antibody-drug conjugate (ADC).

In vitro: Maytansine is a potent microtubule-targeted compound that induces mitotic arrest and kills tumor cells at sub-nanomolar concentrations. Maytansine at a concentration of 100 nmol/L suppressed the growth and shortening rates by 35%, quantitatively similarly to the same concentration of vinblastine.  maytansine inhibits the formation of a cross-link between Cys 12 and Cys 201