The primary structure of UK114 tumor antigen

UK114 is a tumor antigen expressed by various malignant neoplasms. The complete amino acid sequence of UK114 purified from goat liver has been determined by automated Edman degradation of CNBr and endoproteinase Lys-C peptides. The protein contains 137 amino acid residues. which corresponds to a molecular mass of 14,229 Da. MALDI-TOF analysis resulted in a molecular weight of 14,290, suggesting that the N-terminal Met residue is acetylated. Sequence comparison shows that UK114 from goat liver (1) has 77% identity with a previously described 23 kDa protein from rat liver (Levy-Favatier et al. (1993) Eur. J. Biochem. 212, 665-673), (2) shares a very high degree of similarity with a family of prokaryotic and eukaryotic hypothetic proteins whose function have not yet been characterized, and (3) exhibits a significant similarity to a group of tumor-associated antigens which belongs to a superfamily of heat shock proteins, acting as possible targets for the host's antitumor immunity.