The protein(s) encoded by the c-myc locus have been examined in specific cell lines and will be investigated in those cells which have their myc gene activated by amplification or bychromosomal translocation. To probe these myc protein(s), polyclonal antibodies have been prepared against peptides representing putative amino acid sequences deduced from the DNA sequence of the myc exons. The myc protein, biosynthetically labeled with radioactive amino acids, has been highly purified by immunoaffinity chromatography. To determine where in the myc exons the protein corresponds, the N-terminal amino acid sequences of myc protein are being analyzed. Other methods for the purification of the myc protein using HPLC are being developed to maintain the myc in its native state. It is important to isolate myc in its non-denaturated state so that its molecular weight, subunit structure, location in the cell, and DNA binding properties may be determined.