A complementary DNA (cDNA) clone encoding a 719-amino acid (aa) protein was isolated, which has a 49% aa identity with budding yeast CDC47, a member of the MCM family. Antiserum raised against a C-terminal polypeptide bacterially produced from the cDNA clone detected a cellular protein about 80 kDa, which coincides with the size of the in vitro transcription/translation product of the cDNA. These results indicate that the cDNA covers the entire coding region of a human homologue of CDC47.