Tumor-associated membrane protein (EMP-1) is a glycoprotein that is highly expressed in brain tumor cells but not in normal brain. It is also expressed at high levels in undifferentiated embryonic stem cells, but markedly down-regulated in these cells after their differentiation into embryoid bodies. The EMP amino acid sequence bears high homology to the growth arrest specific protein PMP22/GAS-3, which is involved in several human peripheral neuropathies.The synthetic peptide used to raise the antibody Cat. No. 251207 is selected from a sequence within the center region of mouse EMP-1. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.