Tubulysin B is a highly cytotoxic peptide and potent microtubule destabilizing agents isolated from the myxobacteria Archangium geophyra and Angiococcus disciformis. Tubulysin B has IC50 values in the picomolar range against many cancer cell lines, including those with multidrug resistant properties[1].Tubulysin B is a cytotoxic activity tubulysin which inhibits tubulin polymerization and leads to cell cycle arrest and apoptosis[2].

Tubulysin B has IC50s of 0.6 and 0.9 nM against KB and A549 tumors cell lines, respectively.

[1]. Leamon CP, et al. Prostate-Specific Membrane Antigen-Specific Antitumor Activity of a Self-Immolative Tubulysin Conjugate. Bioconjug Chem. 2019 Jun 19;30(6):1805-1813. [2]. Vlahov IR, et al. Acid mediated formation of an N-acyliminium ion from tubulysins: a new methodology for the synthesis of natural tubulysins and their analogs. Bioorg Med Chem Lett. 2011 Nov 15;21(22):6778-81.