Santa Cruz Biotechnology offers an expansive library of transfected lysates that overexpress growth factors and hormones. Ephrins, which act as ligands for Eph receptors, are cell-surface proteins which fall into two categories, ephrin-A and ephrin-B, based on their structure and function. Eph receptors and ephrins exhibit complementary expression in many tissues during embryogenesis indicating that bidirectional activation of Eph receptors and ephrin-B proteins may occur at expression domain interfaces. Mouse, rat, human and Xenopus laevis ephrin-B1 are phosphorylated on Tyr 317 in vivo, which may be induced by a receptor tyrosine kinase. A total of three members of the transforming growth factor beta (TGFβ) family, TGFβ1, TGFβ2 and TGFβ3, have been identified in mammals. Transfected lysates that express growth factors and hormones offer a reliable means to evaluate antibody quality and serve as excellent positive controls for experiments involving antibodies.