Pervanadate is a protein tyrosine phosphatase inhibitor that is commonly used to increase tyrosine phosphorylation in cells. Human aortic endothelial cells treated with pervanadate for 30 minutes display a significant increase in tyrosine phosphorylation as shown by western blotting using anti-Phosphotyrosine. Confluent cultures of human aortic endothelial cells were serum starved overnight. Cells were then either left untreated or treated with pervanadate (1mM) for 30 minutes at 37°C. Cells were lysed in 1% SDS, 1mM sodium ortho-vanadate, 10mM Tris (pH 7.4) buffer. Protein concentration was determined using the BCA method (Pierce) before diluting to final concentration and buffer.