8.A.131.1.16
Thrombin-like enzyme gyroxin B1.3 or VSP13 of 262 aas and 1 N-terminal TMS.  It is a thrombin-like snake venom serine protease that displays a specificity similar to trypsin and releases only fibrinopeptide A in the conversion of fibrinogen to fibrin. It reversibly increases the permeability of the blood brain barrier (BBB) in mice (Alves da Silva et al. 2011). It also induces the barrel rotation syndrome in mice, which is manifested by gyroxin-like, rapid rolling motions (Camillo et al. 2001, Alves da Silva et al. 2011). This syndrome may be due to its effect on BBB permeability, and certainly also to other actions affecting endogenous substrates present in the endothelium, nervous tissues or blood.  It also shows a moderate inhibitory activity on the human voltage-gated potassium channel Kv10.1/KCNH1/EAG1 (58% current inhibition at 5 uM) (Boldrini-França et al. 2020).  It blocks Kv10.1/KCNH1/EAG1 in a time and dose-dependent manner and with a mechanism independent of its enzymatic activity.  It may have a preference in interacting with Kv10.1/KCNH1/EAG1 in its closed state, since the inhibitory effect of the toxin is decreased at more depolarized potentials.