(-)-Blebbistatin is one of the configurations of the racemic mixture (±)-Blebbistatin (Cat. No. GC12341) and is the active form. (-)-Blebbistatin is a cell-permeable inhibitor of non-muscle myosin II ATPase, which effectively inhibits multiple striated muscle myosins as well as vertebrate non-muscle myosins with IC50 values ranging from 0.5-5μM, and only slightly inhibits smooth muscle myosin (IC50=80μM) [1, 2]. (+)-Blebbistatinb has no effect on the ATPase activity of various myosin IIs or cell migration in cultured smooth muscle[3]. Blebbistatin is a potential photodynamic agent that can kill cancer cells. Exposure to UV light with a wavelength below 488nm can also lead to rapid inhibition of Blebbistatin [4].
In vitro, (-)-Blebbistatin (10-200μM) was used to treat five human cell lines, including F11-hTERT, U87, Du145, FEMX-I, and LNCaP, for 24h, which inhibited cell viability in a concentration-dependent manner. At the highest dose of 200μM, the survival rates of F11-hTERT cells were approximately 20%, U87 cells were 30%, and Du145, FEMX-I, and LNCaP cells were all below 10%[5]. Treatment with (-)-Blebbistatin (10μM) on intact and skinned isolated rat heart trabeculae, intact rat cardiomyocytes, and single rabbit psoas myofibrils reduced twitch force and cell shortening, decreased the contractility of trabeculae with intact membranes, without affecting tension-dependent myofilament ATPase activity[6].
References:
[1] Lucas‐Lopez C, Patterson S, Blum T, et al. Absolute Stereochemical Assignment and Fluorescence Tuning of the Small Molecule Tool,(–)‐Blebbistatin[J]. 2005.
[2] Limouze J, Straight A F, Mitchison T, et al. Specificity of blebbistatin, an inhibitor of myosin II[J]. Journal of Muscle Research & Cell Motility, 2004, 25: 337-341.
[3] Watanabe M, Yumoto M, Tanaka H, et al. Blebbistatin, a myosin II inhibitor, suppresses contraction and disrupts contractile filaments organization of skinned taenia cecum from guinea pig[J]. American Journal of Physiology-Cell Physiology, 2010, 298(5): C1118-C1126.
[4] Sakamoto T, Limouze J, Combs C A, et al. Blebbistatin, a myosin II inhibitor, is photoinactivated by blue light[J]. Biochemistry, 2005, 44(2): 584-588.
[5] Mikulich A, Kavaliauskiene S, Juzenas P. Blebbistatin, a myosin inhibitor, is phototoxic to human cancer cells under exposure to blue light[J]. Biochimica et Biophysica Acta (BBA)-General Subjects, 2012, 1820(7): 870-877.
[6] Farman G P, Tachampa K, Mateja R, et al. Blebbistatin: use as inhibitor of muscle contraction[J]. Pflügers Archiv-European Journal of Physiology, 2008, 455(6): 995-1005.