Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have compared the immunoreactive oxytocin neurophysin from the human pineal gland with human neurohypophyseal neurophysin. The two proteins were reduced and carboxymethylated with [14C]-iodoacetic acid. Since the pineal protein was available only in a very small amount, we were obliged to use [12C]-carboxymethyl apomyoglobin as a nonalkylatable carrier. The trypsin and subtilisin digests of the two labelled proteins were compared by high-voltage electrophoresis on paper, partition paper chromatography, and high-performance liquid chromatography. The distribution of radioactivity in the above peptide separations suggests a great similarity between the two proteins and few significant differences. As far as we are aware, this study is the first attempt to analyze an extrahypophyseal neurophysin at the molecular level.
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PMID:Similarity of pituitary and pineal human oxytocin neurophysins indicated by peptide mapping after radioactive alkylation and proteolysis. 390 Jul 91

The completed amino-acid sequence of bovine neurophysin-II, a major neurohypophyseal hormone-binding protein in the hypothalamo-neurohypophyseal complex of cows, set the stage for the localization of the disulfide bonds of this sulfur-rich molecule. Neurophysin-II was digested with subtilisin or a pepsin-trypsin mixture. The resulting peptides were subjected to first-dimensional electrophoresis at pH 6.5, oxidized with performic acid, and subjected to second-dimensional electrophoresis under identical conditions as the first-dimensional separation, but in a perpendicular direction. Cysteic acid peptides were eluted (several after additional electrophoretic purification at pH 3.5) for amino-acid composition and NH(2)- and COOH-terminal analyses. Our assignment of the seven disulfide bridges present in neurophysin-II is as follows: Cys(10)-Cys(93); Cys(13)-Cys(95); Cys(21)-Cys(27); Cys(28)-Cys(44); Cys(54)-Cys(61); Cys(67)-Cys(73); Cys(74)-Cys(79). The assignment of disulfide bridges associated with Cys(27) and Cys(28) is tentative as it is derived from evolutionary consideration. The high disulfide content reduces drastically the allowed number of biofunctional conformers of neurophysin-II. It is suggested that neurophysin-II possesses a globular topography with minimal alpha-helix structure.
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PMID:Covalent structure of bovine neurophysin-II: localization of the disulfide bonds. 456 11

Attention has focused recently on the role of amino-terminal precursor pro regions in protein folding, with particular emphasis on their effects on folding kinetics. We examined the kinetic and thermodynamic effects of ligand peptides on the folding of neurophysin from the reduced state; these peptides serve as analogs of the pro regions of the common precursors of the neurophysins and the hormones oxytocin and vasopressin. Folding of reduced, mononitrated bovine neurophysin-II was monitored by circular dichroism in a glutathione redox buffer. The results confirmed the ability of neurophysin to fold to a limited extent (20-25% in this system) in the absence of ligand peptides. Ligand peptides increased the efficiency of folding to 100%, the exact efficiency being dependent on peptide identity and concentration. However, the rate of folding was peptide-independent. Analysis of the folding reaction demonstrated relatively rapid conversion of the reduced state to a disulfide-scrambled state, which slowly converted (half-life of 5 h at pH 7.3) to the folded state. Native unliganded neurophysin also equilibrated with the disulfide-scrambled state in the same redox buffers. For each peptide, an equilibrium constant for the folding reaction, representing the amount of peptide bound in the folding system as a function of peptide concentration, was calculated. Comparison of this constant with the intrinsic binding constants of the native protein allowed the derivation, under conditions at or approaching thermodynamic reversibility, of the relative stability of the native and disulfide-scrambled states. The results indicate that the scrambled state, which probably represents the presence of incorrect disulfide pairs in both protein domains, is more stable than the native unliganded state by approximately 1 kcal/mol in this system. The role of ligand peptide therefore is to stabilize the folded protein after it is formed, i.e., it provides a thermodynamic sink. The results contrast with the putative behavior of exogenous peptides representative of the pro regions of subtilisin and alpha-lytic protease, which are generally considered to facilitate folding by reaction with folding intermediates. A potential alternative view of the role of propeptides in protease folding is suggested.
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PMID:Thermodynamic role of the pro region of the neurophysin precursor in neurophysin folding: evidence from the effects of ligand peptides on folding. 854 67

We have investigated the roles of full-length and carboxyl-terminus-truncated forms of the subtilisin-like prohormone convertase SPC3 in the processing of the radiolabeled vasopressin and oxytocin precursors, in vitro. We found SPC3 cleaves provasopressin at both the vasopressin-neurophysin and neurophysin-glycopeptide processing sites. Prooxytocin is cleaved by SPC3 at the oxytocin-neurophysin cleavage site. However, our results reveal differences in processing of provasopressin by the different molecular forms of SPC3. In incubations where the rate of autocatalytic carboxyl-terminus truncation of SPC3 was dramatically reduced, 86-kDa SPC3, which has an unprocessed carboxyl terminus, cleaved provasopressin at the neurophysin-glycopeptide junction. Cleavage at the vasopressin-neurophysin junction only occurred with the appearance of carboxyl-terminus-truncated forms of the enzyme. Incubations containing 64-kDa SPC3 or 64-kDa SPC3-T, a recombinant form of SPC3 truncated 14 amino acids beyond the conserved carboxyl-terminal "P-domain," rapidly cleaved provasopressin at both the vasopressin-neurophysin and neurophysin-glycopeptide junctions. Our results also suggest that prooxytocin is unable to be cleaved by the 86-kDa form of SPC3. We propose that SPC3 should be considered as a candidate endoprotease in the biosynthesis of vasopressin. Furthermore, we suggest that the carboxyl terminus of SPC3 alters the cleavage specificity of SPC3.
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PMID:Differential cleavage of provasopressin by the major molecular forms of SPC3. 952 85