Figure 1. Proteolytic effect of Loxosceles intermedia venom on purified extracellular matrix molecules*. EHS-laminin (A), rat tail tendon type I collagen (B), human placental type IV collagen (C), human fibrinogen (D), human fibronectin (E), human vitronectin (F) and EHS-laminin/entactin dimer (G) were incubated with venom (+) or in the absence of venom, as controls for experimental stability (-) under the conditions described in References 19, 20, 21 and 57. The products obtained were analyzed by SDS-PAGE under reducing conditions (except for fibrinogen that was analyzed under nonreducing conditions). In panel A the open arrow indicates the laminin a₁ chain and the filled arrow indicates the ß₁ and g₁ laminin chains that co-migrate. In panel B the open arrow indicates the type I collagen ß dimers, the filled arrow depicts a₁ type I collagen chain and the filled arrowhead indicates the a₂ type I collagen chain. In panel C the asterisks represent the major components of trypsin-extracted human placental type IV collagens of 100, 160 and 170 kDa. In panel D the open arrow points to an intact fibrinogen molecule and the filled arrow indicates the fibrinogen fragment. In panel E the open arrow shows the co-migratory fibronectin A and B chains, and asterisks indicate fibronectin fragments. In panel F the open arrow points to the 75-kDa vitronectin molecule and the filled arrow points to the 65-kDa normally processed vitronectin fragment. In panel G the open arrow indicates the laminin a₁ chain, the filled arrow indicates the ß₁ and g₁ laminin chains that co-migrate, the open arrowhead indicates intact entactin, the filled arrowhead indicates the 100-kDa entactin fragment, and the asterisk shows the 50-kDa entactin fragment. *Based on results from References 19, 20, 21 and 57.