Analysis of the protein and glycan parts of CA125 antigen from human amniotic fluid

CA 125 antigen is a mucin-type molecule with a complex protein backbone and oligosaccharide chain structure. In this study, we characterized CA 125 antigen from human amniotic fluid by gel filtration, ion-exchange chromatography, peptide mass fingerprinting and lectin-binding assays. The obtained results indicate CA 125 to be structurally heterogeneous, existing in different glycoisoforms with subtle differences in the profile of molecular forms in comparison to placental tissue-derived and cancer-derived CA 125 antigen. The complexity of CA 125 structure suggests that it can act as a multifunctional molecule. Further investigation is therefore needed in order for the biological meaning of the tissue-specific structural forms to be comprehended fully.