Fig. 4From: Polysialic acid is released by human umbilical vein endothelial cells (HUVEC) in vitroInteraction of polySia with VEGF. In binding assays, the indicated proteins (2 µg each) were incubated with increasing doses of polySia (1–4 µg/mL as shown), and the reaction mixtures were applied to native gel electrophoresis. The control lane (−) contained only polySia but no protein. Proteins were visualized by staining with Coomassie BlueBack to article page