Mastoparan (trifluoroacetate salt)

Mastoparan is a mast cell degranulating peptide originally isolated from Vespid wasp venom.¹ It promotes degranulation by increasing GTPase activity for G_i and G_o signaling independent of G protein-coupled receptor binding.^2,3 Mastoparan also binds calmodulin (K_d = 0.3 nM) and inhibits the calmodulin-induced activation of phosphodiesterase (IC₅₀ = 0.02 µM).^4,5 In vitro, mastoparan was effective in killing leukemia, myeloma, and breast cancer cells (IC₅₀s = 8-9.2, 11, and 20-24 µM, respectively).⁶ It worked synergistically with gemcitabine in a mouse model of mammary carcinoma.⁶

1.Hirai, Y., Yashuhara, T., Yoshida, H., et al.A new mast cell degranulating peptide "mastoparan" in the venom of Vespula lewisiiChem. Pharm. Bull. (Tokyo)27(8)1942-1944(1979) 2.Higashijima, T., Uzu, S., Nakajima, T., et al.Mastoparan, a peptide toxin from wasp venom, mimics receptors by activating GTP-binding regulatory proteins (G proteins)J. Biol. Chem.263(14)6491-6494(1988) 3.Higashijima, T., Burnier, J., and Ross, E.M.Regulation of Gi and Go by mastoparan, related amphiphilic peptides, and hydrophobic amines. Mechanism and structural determinants of activityJ. Biol. Chem.265(24)14176-14186(1990) 4.Malencik, D.A., and Anderson, S.R.High affinity binding of the mastoparans by calmodulinBiochem. Biophys. Res. Commun.114(1)50-56(1983) 5.Barnette, M.S., Daly, R., and Weiss, B.Inhibition of calmodulin activity by insect venom peptidesBiochem. Pharmacol.32(19)2929-2933(1983) 6.Hilchie, A.L., Sharon, A.J., Haney, E.F., et al.Mastoparan is a membranolytic anti-cancer peptide that works synergistically with gemcitabine in a mouse model of mammary carcinomaBiochim Biophys. Acta.1858(12)3195-3204(2016)