Characterization of the 80,000 molecular weight form of neurophysin isolated from bovine neurohypophysis.
Partially purified immunoreactive species extracted from bovine posterior pituitary have been labeled with 125I and analyzed by immunoprecipitation with antineurophysin antibodies followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Under denaturing, but nonreducing conditions, a band of Mr = 80,000 was observed. This band corresponded to immunoreactive species detected by radioimmunoassay after chromatography of unlabeled material on a Sepharose CL-4B gel filtration column run in the presence of 6 M guanidine hydrochloride. Under nondenaturing conditions, this species behaved like molecules with an apparent Mr of 140,000 to 160,000. Electrophoretic analysis of the immunoprecipitated material showed that it contained an immunoreactive, single polypeptide chain of Mr = 80,000. Another immunoreactive species of similar molecular weight was also detected, apparently derived from the first one by peptide bond cleavage yielding two fragments of Mr = 68,000 and 10,000, respectively, held together by disulfide bridges. The Mr = 68,000 fragment had lost immunoprecipitability, although its peptide map was largely homologous to that or Mr = 80,000 polypeptide. The 10,000 piece was shown by radioimmunoassay and peptide analysis to be homologous to neurophysin.
D000818:Animals; D000936:Antigen-Antibody Complex; D002417:Cattle; D007106:Immune Sera; D008970:Molecular Weight; D009481:Neurophysins / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000032:analysis; D010904:Pituitary Gland, Posterior / Q000032:analysis*; D011863:Radioimmunoassay; D014357:Trypsin
D000936:Antigen-Antibody Complex; D007106:Immune Sera; D009481:Neurophysins; D010446:Peptide Fragments; D014357:Trypsin