Voltage-gated sodium channels (Nav) gating-modifier. Acts both as alpha- and beta-toxin, since it affects not only activation but also inactivation of Nav channels (PubMed:25862296) (Probable). Binds to Nav domain DII and impairs the four Nav channel voltage sensors movements (PubMed:17698594, PubMed:19005548). Depending on Nav channel subtypes tested, can also bind Nav domains DIII (low affinity) and DIV (very low affinity) (PubMed:17698594, PubMed:19005548, PubMed:25624450). Acts on almost all the Nav channels tested (mammalian Nav1.2/SCN2A, Nav1.3/SCN3A, Nav1.4/SCN4A, Nav1.5/SCN5A, Nav1.6/SCN8A, Nav1.9/SCN11A, and insect DmNav1) (PubMed:9048656, PubMed:17698594, PubMed:21670206, PubMed:24989851, PubMed:25862296, PubMed:31012002). Is highly active against both mammals and insects (PubMed:17118417, PubMed:21549737). Irreversibly modulates DmNav channels (PubMed:25862296). Other Ts1 activities have been studied, such as immunomodulation, antimicrobial activity or exocrine secretion (Probable). This toxin exhibits an antifungal activity against filamentous fungi (PubMed:28634472). In vitro, it has an important immunomodulatory effect on macrophages by stimulating the release of pro-inflammatory cytokines (PubMed:21549737). It also shows an activity in exocrine secretion in pancreas, stomach and adrenal gland (PubMed:1993690, PubMed:9611141, PubMed:10347806). Optimum pH is 4.5-7.5. Is almost completely inactivated at pH 11.5. Optimum temperature is 25-60 degrees Celsius. All temperatures tested are optimal. Expressed by the venom gland. Has the structural arrangement of an alpha-helix connected to antiparallel beta-sheets by disulfide bonds (CS-alpha/beta). C-terminal amidation is important for high activity. LD(50) is 4.7 ug by subcutaneous injection into mice (235 ug/kg). LD(50) is 826 +/- 156 ug/kg by intravenous injection into mice. LD(50) is 11 +/- 9 ug/kg by intracistenal injection into mice. LD(50) is 0.6 ng by intracerebroventricular injection into mice (30 ng/kg). LD(50) is 1.7 ng by intracerebroventricular injection into mice (85 ng/kg). Is the main neurotoxin of the venom of T.serrulatus. Does not show activity on Nav1.1/SCN1A, Nav1.7/SCN9A, Nav1.8/SCN10A and the bacterial NaChBac. Belongs to the long (4 C-C) scorpion toxin superfamily. Sodium channel inhibitor family. The 'mutant' Ts1-G was isolated from the venom before the last step maturation (i.e. amidation) thanks to a right purification technique (PubMed:24560880). It is indicated here as a mutant, since it does not correspond to the mature toxin.