Electrophoretic Identity of Polypeptides From the Nuclear Membrane Ofanthopleura‐associated Zooxanthellae¹

SUMMARY Nonproliferating zooxanthellae from Anthopleura elegantissima were incubated with 3 H‐amino acids for 4–16 hr to uniformly label cell protein. Radioactive proteins from the nuclear membrane were extracted and solubilized for electrophoresis in polyacrylamide gels. Four major electrophoretic species of polypeptides were observed at pH 5.0, 7.0, and 9.0 in an SDS‐urea‐glutathione system. Their molecular weights were estimated to be 32,000, 44,000, 56,000, and 140,000 daltons. All 4 polypeptides are common to the outer as well as inner nuclear envelopes.