Binding of purified αIIbβ3 and αvβ3 to immobilized echistatin and its analogues. Three hundred nanograms per sample of echistatin (○), 300 ng per sample of D27W echistatin (•), and 245 ng per sample of echistatin 1-41 (▿) were immobilized overnight at 4°C on a 96-well ELISA plate in 50 mmol/L carbonate/bicarbonate buffer, pH 9.2. After blocking, the purified receptors were incubated on plate at 37°C for 30 minutes. The amount of bound receptor to disintegrin was detected using MoAb as described in the Materials and Methods. Error bars represent the standard deviations from three experiments.