Production of superoxide dismutase, beta 2-microglobulin and ubiquitin by human term decidua in vitro.

In order to study decidual proteins produced during pregnancy, decidual cells were isolated from term placental membranes by collagenase digestion and Percoll gradient centrifugation. Serum-free CMRL-1066 medium, conditioned for 148 h with the purified decidual cells, was collected and concentrated by ultrafiltration and applied to a Sephadex G-50 column. The protein-containing fractions from the column were concentrated, dialyzed, lyophilized, applied to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and transferred to a polyvinylidene difluoride membrane, followed by sequencing. Superoxide dismutase and two new members of the decidual protein family, beta 2-microglobulin precursor and ubiquitin, were identified by 100% N-terminal sequence homology, and similarities of molecular weights and residue contents.