期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1980
卷号：77
期号：5
页码：2587-2591
DOI：10.1073/pnas.77.5.2587
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Extracts of bovine neurohypophysis made in acid/ethanol solution containing protease inhibitors were fractionated by two successive filtrations on Sephadex G-75 columns equilibrated in the presence and then in the absence of 4 M urea. Analysis of the pattern of neurophysin-like immunoreactivity in the eluate, with two different antibodies, indicated the presence of high Mr forms of neurophysin (apparent sizes, [unk]70,000 and 20,000-25,000, respectively) besides the Mr 10,000 neurophysin. [8-Arginine]vasopressin-like immunoreactivity was also detected, coeluting with the neurophysin-like species, in the material recovered in the exclusion and Mr 20,000-25,000 elution volumes of the same molecular sieve fractionation of neurohypophyseal extracts. Upon subsequent Sephadex G-150 filtration, the immunoreactive material recovered in the exclusion volume of the Sephadex G-75 filtration showed an apparent Mr of approximately 140,000. Both neurophysin-like and vasopressin-like immunoreactivities coeluted in the same volume. The elution profile of this Mr 140,000 material was unmodified when reanalyzed by the same molecular sieve filtration after exposure to 8 M urea. When these Mr 140,000 immunoreactive forms of vasopressin and neurophysin were submitted to affinity chromatography on anti-neurophysin antibodies immobilized on Sepharose, both immunoreactivities were selectively coadsorbed to the immunoadsorbent. Similarly, the neurophysin and vasopressin immunoreactivities associated with Mr{approx}25,000 were retained together on the same anti-neurophysin immunoadsorbent. The Mr 140,000 and Mr 25,000 species having both neurophysin and [8-arginine]vasopressin antigenic determinants generated the two neurosecretory components when exposed to proteolytic activities. This in vitro processing was inhibited in acid medium, at low temperature, and in the presence of a mixture of protease inhibitors. It is concluded that these two large forms of proteins containing both neurophysin and vasopressin may represent common biosynthetic precursors of these two neurohypophyseal components.
