COMPARATIVE STRUCTURAL-ANALYSIS OF HUMAN AND RAT 65KDA TUMOR-ASSOCIATED PHOSPHOPROTEINS

1. A 65 kDa-tumor-associated protein (p65) was isolated from human and rat carcinoma cell culture media. Antibodies raised to the rat protei n recognized an antigenically related protein in human cancer cell lin e. 2. Amino acid composition, N-terminal and internal sequence as well as peptide map and western blot analysis of the p65 strongly suggest a high degree of homology between the human and rat p65 proteins. 3. H omology searches indicated that p65 was not homologous to previously s equenced proteins, but that it may be related to proteins of the stero id receptor superfamily of genes, especially c-erb A gene.