Thrombospondin 1 (TSP1) is a multidomain,Mouse,ultifunctional glycoprotein from platelets and certain vascular cells which has been shown to play an important role in cell-cell and cell-matri, Xenopus/Amphibian, interactions. TSP1 is a calcium-sensitive, disulfide-bonded trimer with a subunit molecular mass of 150 kDa. TSP1 e, Xenopus/Amphibian,ists in different conformational states depending on the calcium ion concentration used in the purification buffers. This antibody is highly specific for the low-calcium conformation (0.1 mmol/l) of human TSP1. There is no evidence of cross-reactivity with other connective tissue proteins (vitronectin, fibronectin, elastin, collagen, laminin). Cross-reactivity with thrombospondins from other species has not been tested.