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Isolation of a trypsin-like enzyme from Streptomyces paromomycinus (paromotrypsin) by affinity adsorption through Kunitz inhibitor-sepharose. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 2009; 8:45-55. [PMID: 1248926 DOI: 10.1111/j.1399-3011.1976.tb02480.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A trypsin-like enzyme has been isolated from the filtrate of a Streptomyces rimosus forma paromomycinus culture. Purification involves acetone fractionated precipitation, ultrafiltration on a Diaflo UM 10 membrane and affinity adsorption on to Kunitz pancreatic trypsin inhibitor linked to Sepharose. The trypsin-like enzyme (paromotrypsin) appears homogeneous by zone electrophoresis on gelatinized cellulose acetate. Specific activity toward Tos-Arg-OMe, calculated from amino acid analysis, is about 220 mu mg-1. The overall yield in activity is about 30%. The molecular weight of the trypsin-like enzyme, determined by gel filtration, is around 22,000-25,000 daltons. Electrophoretic migration on cellulose acetate strips indicates an isoelectric point around 8. Amino acid composition has been determined; the protein comprises about 210 residues on the basis of a single histidine residue per molecule. Paromotrypsin is unstable in acidic medium and is not stabilized by calcium ions. Enzymic activity towards Bz-Argo-OEt is not increased by the addition of calcium ion in contrast to the activating effect observed on bovine trypsin. Paromotrypsin is inhbited by TLCK and NPGB; it interacts with naturally occurring bovine trypsin inhibitors such as soya bean and Kunitz pancreatic inhibitors, but not with chicken ovomucoid. Proteolytic specificity, examined by hydrolysis of oxidized Kunitz pancreatic inhibitor and characterization of resulting peptides, seems similar to that of bovine trypsin.
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A study of the active center of trypsinogen by comparative affinity chromatography of trypsinogen, alpha-, beta-, psi-trypsins, DIP-trypsin, chymotrypsinogen, alpha-chymotrypsin and elastase. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 2009; 6:37-41. [PMID: 4850322 DOI: 10.1111/j.1399-3011.1974.tb02356.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Identity of trypsin inhibitors isolated from bovine liver and pancreas. INTERNATIONAL JOURNAL OF PROTEIN RESEARCH 2009; 2:165-7. [PMID: 5538523 DOI: 10.1111/j.1399-3011.1970.tb01673.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Molecular evolution of the polypeptide hormones. CIBA FOUNDATION SYMPOSIUM 2008; 41:31-59. [PMID: 780077 DOI: 10.1002/9780470720233.ch3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Any biological function is at least bimolecular and its evolution therefore is at least dual, with variations in two lines of molecules. The hormone specificity results from a particular fit between the three-dimensional structure of the agent and that of the receptor but, because receptors are not known at the structural level, a discussion on the evolution of the polypeptide hormones is mainly limited to the possible progressive changes of the latter. As for other proteins (enzymes, oxygen carriers etc.) two degrees of complexity can be distinguished according to whether the hormone comprises one or several polypeptide chains. Protein assembly can bring new biological properties, each subunit playing a particular role. In this case, the 'internal' evolution (chain-chain interactions) overlaps the 'external' evolution (hormone-receptor contacts). The 'monomeric' hormones present the following problems: evolution of the prohormone and of the converting enzyme (for insulin), duplication and differentiation of two lines of hormones either by amino acid substitutions (neurohypophysial hormones and neurophysins) or by substitutions and size modifications (corticotropin and lipotropin), duplication and fusion leading to internal homology in the single polypeptide chain (somatotropin, prolactin, placental lactogen). The 'dimeric' hormones lead to several problems: successive duplications giving different subunits, selective associations between subunits, unequal rates of evolution of the subunits, the function of each subunit (lutropin, follitropin, thyrotropin, choriogonadotropin). An attempt is made to integrate the evolution of polypeptide hormones in the frame of the evolution of proteins.
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[Water homeostasis in the living: molecular organization, osmoregulatory reflexes and evolution]. ANNALES D'ENDOCRINOLOGIE 2002; 63:197-218. [PMID: 12193876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Human body weight is about 70% water; 55% of the water are in cells and 45% in extracellular compartments, mainly body fluids. Each compartment has its own osmoregulatory system. The mechanisms of intracellular osmoregulation likely appeared with the cell itself, i.e. in primitive prokaryotes, some 3.8 billions years ago. Osmotic stress responses observed in present-day bacteria, yeast, plant and animals cells in culture are very similar. Variations in the cell volume entail an extension or retraction of plasma membrane that activates mechanically-gated ion channels or mechanoreceptors. Some of them have been cloned from E. coli, the nematode C. elegans, the drosophila. Osmotic stress determines an intracellular cascade of transactivations, the last transcription factor binding to a Tonicity response element (TonE) of osmoprotective genes. These genes encode enzymes synthesizing compatible osmolytes that reequilibrate the osmotic pressure. Volume and osmolality of the biological fluids (le milieu intérieur) are regulated by neuroendocrine reflexes involving an afferent neural limb from baro- and osmo-receptors to hypothalamus and an efferent endocrine limb from neurosecretory cells to target cells, the hydroosmotic cells localized in osmoregulatory organs. Afferent signals trigger the biosynthesis and the processing of neurohypophyseal preprohormones in magnocellular neurons of the supraoptic and paraventricular nuclei of hypothalamus. Vasopressin in mammais and vasotocin in other vertebrates, endowed with antidiuretic and antinatriuretic properties, act on hydroosmotic cells localized in the nephron collecting duct. A specific vasopressin receptor, the V2 type receptor, located in the basolateral membrane of the principal cells, is coupled with an heterotridimeric protein Gs that activates adenylate cyclase. The cAMP product, in turn, stimulates the protein kinase A (PKA). The latter mobilizes 5 effectors located in the apical membrane: 1) the water channel aquaporin 2; 2) the urea transporter UT1; 3) the amiloride-sensitive sodium channel ENaC; 4) the inward-rectifying potassium channel ROM-K1; 5) the chloride channel CFTR. Modulation of each effector is ensured by an A kinase anchoring protein (AKAP). The effectors are transported from cytosol to apical membrane through transport vesicles equipped with membrane fusion proteins (such as VAMP2) that recognize specific apical membrane proteins (such as syntaxins). Water flows into principal cells from collecting duct lumen through AQP2 and flows out to interstitium through AQP3 and AQP4 and finally reachs blood circulation through AQP1 capillaries. Vasopressin orchestrates the live effectors so as to keep water and solutes reabsorptions in balance with volaemia and osmolality set points.
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Organismal handling of water balance in vertebrates. SYMPOSIA OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY 2002:169-82. [PMID: 14992151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
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[Neurohypophyseal regulation of osmoregulator systems]. ANNALES D'ENDOCRINOLOGIE 2000; 61:136. [PMID: 10960325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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Unique evolution of neurohypophysial hormones in cartilaginous fishes: possible implications for urea-based osmoregulation. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1999; 284:475-84. [PMID: 10469984 DOI: 10.1002/(sici)1097-010x(19991001)284:5<475::aid-jez2>3.0.co;2-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Most bony vertebrate species display a great evolutionary stability of their two neurohypophysial hormones, so that two molecular lineages, isotocin-mesotocin-oxytocin and vasotocin-vasopressin, have been traced from bony fishes to mammals. Chondrichthyes, in contrast, show a striking diversity of their oxytocin-like hormones, yet show a substantial decrease in vasotocin stored in neurohypophysis when compared to nonmammalian bony vertebrates. In the rays, glumitocin ([Ser(4),Gln(8)]-oxytocin) has been identified. In the spiny dogfish, aspargtocin ([Asn4]-oxytocin) and valitocin ([Val(8)]-oxytocin) have been characterized whereas in the spotted dogfish, asvatocin ([Asn(4),Val(8)]-oxytocin) and phasvatocin ([Phe(3),Asn(4),Val(8)]-oxytocin) have been found. Finally, in the holocephalian Pacific ratfish, oxytocin, the typical peptide of placental mammals, has been discovered. The duplication of the oxytocin-like hormone gene found in dogfishes has been observed only in some Australian and American marsupials. Cartilaginous fishes have developed an original urea-based osmoregulation involving a glutamine-dependent urea synthesis and blood urea retention through renal urea transporters. Furthermore, marine species use a rectal salt gland for sodium chloride excretion. Although vasopressin, in mammals, and vasotocin, in nonmammalian tetrapods, are clearly implied in water and salt homeostasis, the hormones involved in the blood osmotic pressure regulation of elasmobranchs are still largely unknown. It is suggested that the great diversity of oxytocin-like hormones in elasmobranchs expresses a release from an evolutionary receptor-binding constraint, so that amino-acid substitutions reflect neutral evolution. In contrast, the preservation of vasotocin suggests a selective pressure, which may be related to the regulation of renal urea transporter-recruitment mechanisms, as it has been shown for vasopressin in mammals. J. Exp. Zool. 284:475-484, 1999.
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Adaptive evolution of water homeostasis regulation in amphibians: vasotocin and hydrins. Biol Cell 1997; 89:283-91. [PMID: 9468598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Volemia and osmolality homeostasis is ensured in vertebrates through neuroendocrine reflexes, involving an afferent neural branch from baro- and osmo-receptors to hypothalamus and an efferent endocrine branch from secretory neurons to target hydroosmotic cells equipped with receptors and effectors. Whereas the osmoregulatory system in the tadpole comprises three organs, namely gut, kidney and gills, as in freshwater fishes, the adult displays a quaternary strategy with gut, kidney, urinary bladder and skin. In particular, the cutaneous permeability entails a great evaporative water loss when the animal is in the open air, loss that must be compensated by water reabsorption through the nephron and the urinary bladder and mainly by water uptake through the skin. Adaptation occurred at the level of these organs by regulation of their permeability through neurohypophysial hormones. Aside from vasotocin, active on the three organs, all anuran Amphibia possess hydrin 2 (vasotocinyl-Gly), a peptide resulting from a down-regulation of provasotocin processing. Exceptionally Xenopus laevis, a permanent aquatic toad, has hydrin 1 (vasotocinyl-Gly-Lys-Arg) instead of hydrin 2. Hydrins are somewhat more active than vasotocin on water permeation of skin and bladder but are devoid of antidiuretic activity. Adaptive evolution has created, along with the vasotocin-nephron system, preserved in all terrestrial non-mammalian tetrapods, additional functions such as the hydrin-skin and hydrin-bladder rehydration mechanisms. Specific hydrin receptors might exist in the skin and the bladder, different from those of vasotocin in the kidney. It is assumed that the water channel recruitment mechanism, found for vasopressin acting on the collecting duct principal cells in mammals, is also involved when vasotocin and hydrins stimulate their hydroosmotic target cells and that hormone-regulated aquaporin 2-like proteins could be identified in the three osmoregulatory organs of amphibians.
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Abstract
Chemical identification of neurohypophysial hormones from about 80 vertebrate species reveals that two evolutionary lineages can be traced in bony vertebrates, a vasopressin-like hormone line and an oxytocin-like hormone line, which were derived from the duplication of an ancestral gene that may have been present in agnathans. All of the 13 neurohypophysial hormones are built in the same structural pattern, namely, a nonapeptide with a disulfide bridge linking half-cystines in positions 1 and 6. There is a striking evolutionary stability in bony vertebrates since virtually all species belonging to a given class are endowed with the same peptides. In contrast, in cartilaginous fishes, the oxytocin-like hormone displays a great diversity. Six distinct peptides are characterized in this group. The proposed hypothesis is that the stability in primary structure in bony vertebrates is due to selective pressure. This selective pressure is associated with an ion-based osmoregulation, whereas in Chondrichthyes the occurrence of an urea-based osmoregulation has relieved the hormones from the control of ionic homeostasis. Variations in primary structures in cartilaginous fishes are regarded as relevant to the neutral evolution as defined by Kimura. According to this concept, oxytocin of placental mammals results from selective evolution, whereas the same molecule found in ratfish proceeds from random genetic drift.
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Distinct hydro-osmotic receptors for the neurohypophysial peptides vasotocin and hydrins in the frog Rana esculenta. Neuropeptides 1995; 29:301-7. [PMID: 8587666 DOI: 10.1016/0143-4179(95)90039-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The biological properties of vasotocin, hydrin 1 (vasotocinyl-Gly-Lys-Arg) and hydrin 2 (vasotocinyl-Gly), in particular the hydro-osmotic activities on the frog skin, the frog urinary bladder and the frog kidney, have been compared. Hydrins are as active or more active than vasotocin on the first two organs but they are virtually devoid of antidiuretic activity in the rat and the frog, in contrast to vasotocin. It appears that where the oxytocin ring (residues 1-6), present in the three peptides, is necessary for the action on the three organs, the C-terminal amidated group of vasotocin is necessary for the renal receptor but not for the skin and bladder receptors. It is known that amphibians have two types of vasotocin receptors, V1 and V2, homologous to the vascular/hepatic V1 and the renal V2 vasopressin receptors of mammals, respectively. We suggest that adaptation has led to specialization of (at least) two subtypes of hydro-osmotic V2 receptors, the renal subtype on which vasotocin is mainly active for the reabsorption of tubular water, and the skin/bladder subtype on which hydrin 2 is specifically involved in ensuring the rehydration of the animal. Cooperative evolution might have created in anuran Amphibia, on the one hand, two hydro-osmotic peptides, vasotocin and hydrin 2, derived from a single precursor through differential processing; and on the other hand, two corresponding receptors in kidney and skin for internal and external water recovery.
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Abstract
The neurohypophysial endocrine regulatory cascade has been described as a molecular model of neuroendocrine control of organismal functions. Any physiological function can be analyzed in molecular terms as a succession of interactions occurring either in a solution or in a membrane system. The key mechanism in the ordering of the cascade is the conformational recognition of the two partners at each step. Each interaction results in a change of conformation of a recognized protein that in turn becomes a recognizer for the following molecule. The cascade starts within the secretory cell by the processing of the expressed precursor along the secretory pathway until the storage of the mature mediator in vesicles and its subsequent exocytic secretion in blood. The circulating mediator recognizes the target cell through specific membrane receptors that transduce the message within this target cell. A second intracellular cascade leads to activation of the effector, the protein fulfilling the physiological function. The complexity of the messages is, in part, due to the duplication propensity of the genomic DNA, the frequent occurrence of multiple copies for precursors, mediators, receptors, and effectors, and therefore, a combinatorial diversity that increases during the course of evolution. Vertebrate neurohypophysial hormones can be ordered in two main evolutionary lineages, culminating in oxytocin and vasopressin in placental mammals. In this field, diversification of the messages was made by differential processing of the precursors, secondary gene duplications, the emergence of several types of receptors for each hormone, and a variety of effectors triggered by the second messengers within differentiated target cells. This review is an attempt to integrate neurohypophysial functions at the molecular, cellular, and organismal levels.
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A new neurohypophysial peptide, seritocin ([Ser5,Ile8]-oxytocin), identified in a dryness-resistant African toad, Bufo regularis. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1995; 45:482-7. [PMID: 7591488 DOI: 10.1111/j.1399-3011.1995.tb01064.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
From the pituitary neurointermediate lobe of the African toad Bufo regularis, vasotocin, hydrin 2 (vasotocinyl-Gly) and a mesotocin-like peptide have been isolated by HPLC and characterized by mass spectrometry, amino acid sequence and chromatographic coelution with synthetic peptides. The mesotocin-like peptide has been identified as [Ser5,Ile8]-oxytocin in place of mesotocin ([Ile8]-oxytocin) found in all other amphibians investigated to date. The name seritocin is suggested. The molecule is virtually devoid of oxytocic activity on rat uterus in contrast to mesotocin. On the other hand, the molar ratio of hydrin 2 to vasotocin in the pituitary reaches 2, whereas it is about 1 in toads and frogs from temperate regions. B. regularis is an anuran species able to withstand a hot and dry season by burrowing. The possible relationship between occurrence of seritocin and adaptation to arid environment remains to be demonstrated.
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Special evolution of neurohypophysial hormones in cartilaginous fishes: asvatocin and phasvatocin, two oxytocin-like peptides isolated from the spotted dogfish (Scyliorhinus caniculus). Proc Natl Acad Sci U S A 1994; 91:11266-70. [PMID: 7972045 PMCID: PMC45208 DOI: 10.1073/pnas.91.23.11266] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
In contrast to most vertebrate species that possess one oxytocin-like hormone and one vasopressin-like hormone, a few groups, such as marsupials or cartilaginous fishes, are endowed with two peptides of either or both types, suggesting possible gene duplications. We have now isolated two oxytocin-like hormones from the pituitary of the spotted dogfish Scyliorhinus caniculus (suborder Galeoidei). Microsequencing as well as chromatographic and pharmacological comparisons with synthetic peptides show that these peptides are [Asn4,Val8]oxytocin (asvatocin) and [Phe3,Asn4,Val8]-oxytocin (phasvatocin). Asvatocin and phasvatocin display oxytocic activity on rat uterus, about 80 and 5 milliunits per nmol, respectively, and virtually no pressor activity on anesthetized rats. They occur in roughly equal molar amounts in the gland; vasotocin is also present in a proportional amount that is lower by about a factor of 20. In addition to the duality, conservative amino acid substitutions are observed in the two oxytocic peptides in positions 4 (Gln-4-->Asn) and 8 (Leu-8-->Val), when compared with oxytocin. Furthermore, replacement of the isoleucine residue found in position 3 of all other oxytocin-like hormones by phenylalanine in phasvatocin is exceptional; it determines a dramatic decrease of the oxytocic activity. Preservation of the C-terminal-amidated nonapeptide pattern in the 12 vertebrate neurohypophysial hormones known to date suggests that both precursors and processing enzymes have coevolved tightly. On the other hand, whereas the great evolutionary stability of the mature hormones (generally observed in vertebrates) suggests a strict messenger-receptor coevolution, the exceptional diversity found in cartilaginous fishes (six oxytocin-like peptides identified out of eight known) might be due to a looseness of selective constraints, perhaps in relationship with their specific urea osmoregulation.
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Action of neurohypophysial granule Lys-Arg endopeptidase on synthetic polypeptides comprising the processing sequence of provasopressin-neurophysin. Biosci Rep 1994; 14:171-8. [PMID: 7849239 DOI: 10.1007/bf01200246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Neurohypophysial granule Ca(2+)-dependent endopeptidases have been allowed to act on synthetic polypeptides derived from the N-terminal sequence of bovine provasopressin-neurophysin, namely vasopressinyl-glycyl-lysyl-arginyl-alanylamide and vasopressinyl-glycyl-lysyl-arginyl-alanyl-methionyl-serinamide+ ++. Membrane-bound enzymes have been used at pH 5.5 for 16 hr at 37 degrees C. Products have been identified by high-pressure liquid chromatography (HPLC) and by mass spectrometry performed on substances isolated by HPLC. With both substrates, vasopressinyl-Gly-Lys-Arg(OH) has been identified as a product confirming the Lys-Arg specificity previously observed on small peptide fluorogenic substrates. Cleavage yields, however, appear low suggesting that some factors are missing, for example a targeting action of the precursor neurophysin domain to the granule membrane.
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Bony fish neurophysins. Identification of MSEL- and VLDV-neurophysins of the pollack (Pollachius virens). INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1994; 44:130-8. [PMID: 7982756 DOI: 10.1111/j.1399-3011.1994.tb00567.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The two types of neurophysins known in vertebrate species, namely MSEL-neurophysin (vasopressin-like hormone-associated neurophysin) and VLDV-neurophysin (oxytocin-like hormone-associated neurophysin) have been purified from the pollack (Pollachius virens) pituitary through a combination of molecular sieving and high-pressure liquid chromatography (HPLC). Homogeneity has been checked by gel electrophoresis and return in HPLC. The apparent molecular masses measured by SDS-electrophoresis are near 12 kDa, significantly higher than those found for their mammalian homologues (10 kDa). The two types of neurophysins have been recognized through their N-terminal amino acid sequences. The primary structure of MSEL-neurophysin has been partially determined using automated Edman degradation applied on native and reduced-alkylated protein, as well as peptides derived by trypsin or staphylococcal proteinase hydrolyses. Comparison of pollack MSEL-neurophysin with ox, goose and frog counterparts reveals that particular positions in the polypeptide chain are subjected to substitutions and that the numbers of substitutions do not seem closely related to the paleontological times of divergence between the different vertebrate classes.
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Chemical identification of the mammalian oxytocin in a holocephalian fish, the ratfish (Hydrolagus colliei). Gen Comp Endocrinol 1993; 92:260-8. [PMID: 8282175 DOI: 10.1006/gcen.1993.1162] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The neurohypophysial hormones of the ratfish (Hydrolagus colliei), a species belonging to the subclass Holocephali of cartilaginous fishes, have been investigated. An oxytocin-like hormone has been isolated from acetone-desiccated pituitary glands by using successively molecular sieving and high-pressure liquid chromatography. The peptide has been identified as oxytocin by coelution with synthetic oxytocin in HPLC, amino acid sequencing, mass spectrometry, and C-terminal sequencing through carboxypeptidase Y. Vasotocin may be present in a very small amount. Cartilaginous fishes appear to display a great diversity in their oxytocin-like hormones since five different peptides have been identified in rays and sharks that belong to the second subclass Selachii.
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Lungfish neurohypophysial hormones: chemical identification of mesotocin in the neurointermediate pituitary of the Australian lungfish Neoceratodus forsteri. Gen Comp Endocrinol 1993; 91:330-6. [PMID: 8224776 DOI: 10.1006/gcen.1993.1133] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The neurohypophysial hormones contained in the neurointermediate lobe of the pituitary of the Australian lungfish Neoceratodus forsteri have been investigated. Mesotocin was identified by coelution with the synthetic peptide in high-pressure liquid chromatography, by Edman amino acid sequencing, by mass spectrometry, by C-terminal sequencing through carboxypeptidase Y, and cleavage with prolyl endopeptidase. Vasotocin, if present, would be in very small amounts and hydrins were not detected. Oxytocin appears absent. Although Neoceratodus and Protopterus have different habitats, the former being permanently aquatic, the latter burrowing during estivation, the proportions of neurohypophysial hormones stored in neurohypophysis were roughly similar in the two species and not apparently affected by environmental conditions.
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Differential processing of provasotocin: relative increase of hydrin 2 (vasotocinyl-Gly) in amphibians able to adapt to an arid environment. Neuropeptides 1993; 25:139-43. [PMID: 8413858 DOI: 10.1016/0143-4179(93)90094-q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Hydrin 2 (vasotocinyl-Gly) is an intermediate in pro-vasotocin processing found, along with vasotocin, only in the neurohypophysis of anuran amphibians. It increases cutaneous water permeability in the frog and is likely involved in neuroendocrine control of osmoregulation. The relative amounts of vasotocin and hydrin 2 stored in neurohypophysis have been measured on the one hand in amphibian species known not to adapt in dry areas, on the other hand in two species, Bufo regularis (Africa) and Bufo viridis (Near-East) able to survive in an arid environment. In the first group, the proportions of the two peptides are approximately equal whereas in the two toads the molar ratio hydrin 2 to vasotocin reaches 2. The ratio does not appear to vary significantly when these toads are either submitted to dehydration or placed in saline solutions. Predominance of hydrin 2 suggests an adaptive decrease of the activity of the alpha-amidating enzymatic system involved in the conversion of vasotocinyl-Gly into mature amidated vasotocin.
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Neurohypophysial peptide systems: processing machinery, hydroosmotic regulation, adaptation and evolution. REGULATORY PEPTIDES 1993; 45:1-13. [PMID: 8511331 DOI: 10.1016/0167-0115(93)90174-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Vasotocin and hydrin 2 (vasotocinyl-Gly) in the African toad Bufo regularis: study under various environmental conditions. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. COMPARATIVE PHYSIOLOGY 1993; 104:497-502. [PMID: 8097151 DOI: 10.1016/0300-9629(93)90454-c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
1. The neurohypophysial osmoregulatory hormones of the African toad Bufo regularis, a species adapted to estivate under dry and hot conditions, have been investigated. Vasotocin and hydrin 2 (vasotocinyl-Gly) have been identified by their retention times in high-pressure reverse-phase liquid chromatography and coelution with synthetic peptides, their pharmacological properties (vasotocin) and microsequencing. 2. Vasotocin-associated neurophysin (MSEL-neurophysin type) has been characterized by its N-terminal amino acid sequence. 3. In toads subjected to dehydration by evaporation (20% weight loss) or to osmotic stress by immersion in 2% NaCl for 3 hr (6% weight loss), the molar ratio hydrin 2/vasotocin (about 2:1) remained similar to the one observed in control animals. 4. In toads exposed to saline solution, there was a large decrease (roughly 30%) in the amounts of both hormones in the neuro-hypophysis. Environmental conditions for distinct secretions of vasotocin and hydrin 2 remain to be found.
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Processing endopeptidase deficiency in neurohypophysial secretory granules of the diabetes insipidus (Brattleboro) rat. Biosci Rep 1992; 12:445-51. [PMID: 1298435 DOI: 10.1007/bf01122032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The homozygote Brattleboro rat exhibits a hereditary diabetes insipidus due to a deficiency of vasopressin, the antidiuretic hormone. It has previously been shown that in this animal a single nucleotide deletion in the provasopressin gene leads to a mutant precursor with a C-terminal amino acid sequence different from that of the wild-type. However the N-terminal region including the hormone moiety, the processing signal as well as the first two-thirds of the neurophysin is entirely preserved and absence of maturation has to be explained by an additional cause. We show here that the neurohypophysis of the homozygote Brattleboro rat, in contrast to the adenohypophysis, displays a significant decrease in the Lys-Arg processing endopeptidase activity when compared to the heterozygote or the wild-type Wistar. It is suggested that hypothalamic vasopressinergic neurons of the homozygote Brattleboro rat display a deficiency in the processing enzyme in contrast to the oxytocinergic neurons in which processing of prooxytocin is normal.
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A neurosecretory granule Lys-Arg Ca(2+)-dependent endopeptidase putatively involved in prooxytocin and provasopressin processing. Neuropeptides 1992; 22:223-8. [PMID: 1508325 DOI: 10.1016/0143-4179(92)90050-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A Ca(2+)-dependent endopeptidase cleaving at the carboxyl side of the paired Lys-Arg residues has been found in the neurosecretory granules of the rat neurointermediate pituitary. The specificity pattern on synthetic fluorogenic substrates, the inhibitor profile, the pH optimum of 5.0 and the Ca(2+)-dependence are compatible with an involvement of this enzyme in the prooxytocin and the provasopressin processing within the granules. The enzymatic features of the neurohypophysial granule endopeptidase resemble those of the insulinoma granule type II endopeptidase and suggest that the same Ca(2+)-dependent protease or closely related enzymes could be involved in processing Lys-Arg-containing prohormones in neuroendocrine cells.
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Partial conversion of vasopressinyl-Gly-Lys-Arg into pharmacologically active vasopressin through secretory granule carboxypeptidase E and alpha-amidating processing enzymes. BIOCHEMISTRY INTERNATIONAL 1992; 26:739-46. [PMID: 1610378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Vasopressinyl-Gly-Lys-Arg, the first intermediate derived from vasopressin protein precursor, has been converted into mature vasopressin by an "in vitro" two-step reaction through neurohypophysial secretory granule enzymes. Whereas the conversion into vasopressinyl-Gly is virtually complete at pH 5.5 as judged by HPLC, the conversion of vasopressinyl-Gly into vasopressin is weak at pHs 6.0 or 8.0 as judged by HPLC and measure of generated pressor activity. It is suggested that the high conversion yield usually seen in mammalian neurohypophysis, where no intermediate is detected, might be due to additional "in vivo" factors such as particular membrane-association or binding of the intermediate onto a neurophysin carrier.
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Evidence for distinct dibasic processing endopeptidases with Lys-Arg and Arg-Arg specificities in neurohypophysial secretory granules. Biochem Biophys Res Commun 1992; 183:128-37. [PMID: 1543484 DOI: 10.1016/0006-291x(92)91618-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two Ca(2+)-dependent endopeptidases endowed with specificities for paired basic residues have been disclosed in rat and ox neurohypophysial secretory granules. Specificities investigated by using synthetic fluorogenic substrates showed the presence of a Lys-Arg endopeptidase with optimum pH close to the granule pH (5.5) and of an Arg-Arg endopeptidase more active at pH 7.0. Granule extracts have virtually no activity towards Lys-Lys-containing substrate or monobasic substrates. Pro-Gly-Lys-Arg-chloromethylketone appears a very efficient inhibitor for the Lys-Arg enzyme. Soluble and membrane-bound forms of both endopeptidases have been detected. pH-dependence of membrane binding and partitioning into Triton X-114 suggest that the membrane-bound form of Lys-Arg endopeptidase is associated through an amphiphilic alpha-helix. It is proposed that the enzyme Lys-Arg cleaves prooxytocin and provasopressin at their signal sequence Gly-Lys-Arg when these precursors arrive in the neurosecretory granules. The processing proceeds in the granules through carboxypeptidase E and alpha-amidating enzyme complex for giving mature pharmacologically active nonapeptide hormones.
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The hormone-binding site of neurophysins: binding of vasopressin to the N-terminal sub-domain dissected from human MSEL-neurophysin through endopeptidase Lys-C. Neuropeptides 1991; 20:211-6. [PMID: 1812403 DOI: 10.1016/0143-4179(91)90010-g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Human MSEL-neurophysin has been dissected into two halves by endopeptidase Lys-C, taking advantage of a peculiar Lys59-Ala60 bond. Two sub-domains, N-terminal (1-59) and C-terminal (60-93), have been separated. These sub-domains have been purified by reverse-phase high pressure liquid chromatography and identified by their N-terminal sequences. The N-terminal fragment comprises two chains 1-18 and 19-59, because of the presence of a second lysine residue in position 18, whereas the C-terminal fragment (60-93) is a single chain. Hormone-binding experiments have been carried out using vasopressin or vasopressinyl-Gly-Lys-Arg and testing the ability of the hormone-neurophysin complex to precipitate at pH 3.9 with 10% NaCl. The N-terminal sub-domain precipitates in presence of vasopressin in the same way as native neurophysin whereas the C-terminal sub-domain does not. It can be concluded that the hormone-binding site is located in the 1-59 region of neurophysin.
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Study of frog (Rana esculenta) proopiomelanocortin processing in the intermediate pituitary. Identification of alpha-melanotropin, beta-melanotropin, Lys-gamma-melanotropin, and corticotropin-like intermediate lobe peptide. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1991; 37:236-40. [PMID: 1651291 DOI: 10.1111/j.1399-3011.1991.tb00276.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The proteolytic processing of frog (Rana esculenta) proopiomelanocortin in melanotropic cells of the intermediate pituitary gland has been examined through purification of the mature fragments by reverse-phase high-pressure liquid chromatography and microsequencing of isolated peptides. alpha-Melanotropin, beta-melanotropin, Lys-gamma-melanotropin, corticotropin-like intermediate lobe peptide, and hinge peptide have been isolated and chemically characterized. The results show a high preservation in the processing sites of frog proopiomelanotropin when compared to bovine counterparts. They reveal also a great conservation of the processing enzyme equipment of melanotropic cells in tetrapods species. Identification of Lys-gamma-melanotropin suggests the occurrence of an endopeptidase able to cleave between two basic residues. On the other hand alpha-melanotropin does not appear to be N-acetylated, as previously found in the clawed-toad Xenopus laevis, and this feature might distinguish amphibian from mammalian proopiomelanocortin processing.
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Abstract
Abstract Hydrin 2 (vasotocinyl-Gly), found along with vasotocin in the neurohypophysis of frogs and toads but not of other vasotocin-bearers such as birds and reptiles, is believed to act on water permeability of frog skin, whereas vasotocin mainly fulfils the antidiuretic function on the kidney. In order to understand the peculiar regulation of provasotocin differential processing in amphibians, conversion of hydrin 2 into vasotocin has been attempted using bovine pituitary granule alpha-amidating enzyme. Generated vasotocin has pharmacological properties and Chromatographic behaviour in high-performance liquid chromatography identical to those of synthetic vasotocin. However, the low yield of conversion (5% to 10%) suggests that additional factor(s) might be involved in the physiological processing.
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Complete amino acid sequence of goose VLDV-neurophysin. Traces of a putative gene conversion between promesotocin and provasotocin genes. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1990; 36:457-64. [PMID: 2276874 DOI: 10.1111/j.1399-3011.1990.tb01306.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Goose VLDV-neurophysin (mesotocin-associated neurophysin) has been purified from posterior pituitary glands through molecular sieving on Sephadex G-75 and high-pressure reverse-phase liquid chromatography on Nucleosil C-18 columns. Despite apparent molecular mass of unreduced VLDV-neurophysin measured by polyacrylamide gel electrophoresis with sodium dodecylsulfate appeared near 17 kDa, this value fell to 11 kDa after reduction with mercaptoethanol, suggesting the existence of a homodimer. Complete amino acid sequence (93 residues) of goose VLDV-neurophysin has been determined. N- and C-terminal sequences of the protein have been established by Edman degradation (microsequencing) and use of carboxypeptidase Y, respectively. Peptides derived from oxidized or carboxamidomethylated neurophysin by trypsin or staphylococcal proteinase hydrolyses have been isolated by high-pressure liquid chromatography and microsequenced, allowing determination of the complete sequence. Comparison within the vertebrate VLDV-neurophysin lineage, namely goose VLDV-neurophysin to mammalian VLDV-neurophysins and to deduced toad VLDV-neurophysin, reveals a residue insertion between positions 66 and 67 in the nonmammalian VLDV-neurophysins. When goose MSEL-neurophysin (vasotocin-associated neurophysin) and goose VLDV-neurophysin are compared to their bovine counterparts, identical substitutions are found in positions 17 (Asn in both goose neurophysins instead of Gly in both ox neurophysins), 18 (Arg instead of Lys), 35 (Tyr instead of Phe), and 41 (Thr instead of Ala). Identity of the sequences 10-74 in both ox neurophysins has been explained by partial gene conversion between oxytocin and vasopressin genes, and identical substitutions in both goose neurophysins might reveal a similar gene conversion between mesotocin and vasopressin genes in birds.
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Non-mammalian "big" neurophysins--complete amino acid sequence of a two-domain MSEL-neurophysin from goose. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1990; 36:302-7. [PMID: 2279853 DOI: 10.1111/j.1399-3011.1990.tb00983.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Vasotocin-associated neurophysin (MSEL-neurophysin) has been purified from goose neurohypophysis through molecular sieving and high-pressure reverse-phase liquid chromatography (HPLC). The protein has a molecular mass (measured by SDS-polyacrylamide gel electrophoresis) of 17 kDa in contrast to 10 kDa found for the mammalian MSEL-neurophysins. Complete amino acid sequence (131 residues) has been determined mainly through tryptic or staphylococcal proteinase peptides derived from carboxyamidomethylated neurophysin, isolated by HPLC and microsequenced. N- and C-terminal sequences have been established by Edman degradation or action of carboxypeptidase Y, respectively, applied on the native protein. Goose MSEL-neurophysin is homologous to the two-domain "big" MSEL-neurophysin previously identified in the frog. It appears that in non-mammalian tetrapods, namely birds and amphibians, the proteolytic processing of the pro-vasotocin involves only one cleavage, releasing the hormone moiety and a "big" neurophysin with two domains homologous to mammalian MSEL-neurophysin and copeptin, respectively. Comparison of the avian protein with its mammalian and amphibian counterparts reveals that the first half of the polypeptide chain is evolutionarily much less variable than the second and that the goose protein resembles the frog protein much more than the mammalian one.
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Evolutionary specificity of hydrins, new hydroosmotic neuropeptides: occurrence of hydrin 2 (vasotocinyl-Gly) in the toad Bufo marinus but not in the viper Vipera aspis. FEBS Lett 1990; 264:135-7. [PMID: 2110910 DOI: 10.1016/0014-5793(90)80783-f] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Hydrin 2 (vasotocinyl-Gly), a hydroosmotic peptide resulting from differential processing of provasotocin and recently identified in frog neurohypophysis, has been looked for in the pituitary gland of an exotic toad (Bufo marinus) and of a reptile (Vipera aspis). Hydrin 2 has been found in the amphibian but not in the reptile. This result confirms the evolutionary specificity of hydrin 2 that has been identified only in frogs and toads but not in birds and reptiles. Occurrence of hydrin 2 is explained by its regulatory function on the water permeability of the skin of anurans.
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Identification of two types of neurophysins in Xenopus laevis neurointermediate pituitary homologous to mammalian MSEL- and VLDV-neurophysins. Neuropeptides 1990; 15:123-7. [PMID: 2250763 DOI: 10.1016/0143-4179(90)90142-l] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
UNLABELLED Xenopus laevis neurophysins have been purified from neurointermediate pituitaries through high-pressure reverse-phase liquid chromatography and their N-terminal amino acid sequences have been determined by microsequencing. Two types of neurophysins, corresponding to mammalian MSEL- and VLDV-neurophysins, have been distinguished. A strong homology exists between neurophysins of Xenopus (Pipidae), frog (Ranidae) and toad (Bufonidae). Xenopus MSEL-neurophysin, as frog MSEL-neurophysin, has a high molecular mass suggesting that the C-terminal domain of the vasotocin precursor is not processed in contrast to the two-step processing observed for mammalian vasopressin precursor. ABBREVIATIONS Mammalian neurophysins are termed MSEL- and VLDV-neurophysins according to the nature of residues in positions 2, 3, 6 and 7 (one-letter symbols for amino acids).
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Occurrence of hydrin 2 (vasotocinyl-Gly), a new hydroosmotic neurohypophyseal peptide, in secretory granules isolated from the frog (Rana esculenta) neurointermediate pituitary. Neuroendocrinology 1990; 51:233-6. [PMID: 2106101 DOI: 10.1159/000125343] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Neurohypophyseal secretory granules have been purified from the frog (Rana esculenta) neurointermediate pituitary gland by sucrose gradient centrifugation, and their polypeptide content has been analyzed by reverse-phase high-pressure liquid chromatography. Aside from vasotocin, mesotocin, and their associated neurophysins, hydrin 2 (vasotocinyl-Gly), previously identified in hydrochloric acid extracts, has been recognized. This finding supports the previous suggestion that hydrin 2, a peptide active on the water permeability of frog bladder and frog skin, is a secreted hormone involved in osmoregulation specific to amphibians. Hydrin 2 has not been found in neurosecretory granules of birds such as the goose.
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Hydrins, hydroosmotic neurohypophysial peptides: osmoregulatory adaptation in amphibians through vasotocin precursor processing. Proc Natl Acad Sci U S A 1989; 86:5272-5. [PMID: 2787509 PMCID: PMC297603 DOI: 10.1073/pnas.86.14.5272] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
From neurointermediate pituitary glands of Xenopus laevis and Rana esculenta, previously unreported peptides termed hydrins, active on water permeability of frog urinary bladder and frog skin (Brunn or "water-balance" effect), have been isolated and sequenced. These peptides seem to be derived from the pro-vasotocin-neurophysin precursor. Hydrin 1, found in Xenopus, has been identified as vasotocin C-terminally extended with the Gly-Lys-Arg sequence; hydrin 2, found in Rana, has been identified as vasotocin C-terminally extended with glycine. Hydrin 2 has been detected in several Ranidae (R. esculenta, Rana temporaria, Rana pipiens) and Bufonidae (Bufo bufo, Bufo ictericus) and appears to have a large distribution in terrestrial or semiaquatic anurans. Hydrins, in contrast to vasotocin, are not active on rat uterus or rat blood pressure. They are absent from other vasotocin-bearers such as birds and could be involved specifically in water-electrolyte regulation of amphibians.
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Isolation of neurosecretory granules containing vasotocin, mesotocin, MSEL- and VLDV-neurophysins from goose neurohypophysis. Neuropeptides 1989; 13:187-90. [PMID: 2710292 DOI: 10.1016/0143-4179(89)90090-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Neurosecretory granules have been isolated from goose posterior pituitaries and their contents have been analyzed by reverse-phase high-pressure liquid chromatography and polyacrylamide gel electrophoresis. Vasotocin and mesotocin have been identified by their biological activities and their retention times compared with those of synthetic peptides. MSEL- and VLDV-neurophysins have been characterized by their N-terminal sequences, their electrophoretic migrations and their retention times, compared with those of purified goose neurophysins. In contrast to the two-step processing of mammalian provasopressin, processing of the vasotocin - MSEL-neurophysin precursor appears to involve only one cleavage giving the hormone and a "big" MSEL-neurophysin homologous to mammalian MSEL-neurophysin extended by copeptin.
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Particular processing of pro-opiomelanocortin in Xenopus laevis intermediate pituitary. Sequencing of alpha- and beta-melanocyte-stimulating hormones. FEBS Lett 1989; 245:215-8. [PMID: 2564347 DOI: 10.1016/0014-5793(89)80224-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
alpha- and beta-melanocyte-stimulating hormones (alpha-MSH and beta-MSH) have been isolated from Xenopus laevis neurointermediate pituitary and microsequenced. Intracellular alpha-MSH is not N-acetylated after proteolytic processing of pro-opiomelanocortin in contrast to mammalian alpha-MSHs. There is a high preservation of the melanotropic amino acid sequence common to all MSHs although in Xenopus beta-MSH a histidine residue replaces the glutamic acid residue found in position 8 of mammalian beta-MSHs.
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The distribution of lysine vasopressin (lysipressin) in placental mammals: a reinvestigation of the Hippopotamidae (Hippopotamus amphibius) and Tayassuidae (Tayassu angulatus) families. Gen Comp Endocrinol 1988; 71:475-83. [PMID: 3192070 DOI: 10.1016/0016-6480(88)90277-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The neurohypophyseal hormones of the hippopotamus (Hippopotamus amphibius) and collared peccary (Tayassu angulatus) were isolated by molecular sieving and preparative high-pressure liquid chromatography (HPLC). Oxytocin and arginine vasopressin have been identified by their amino acid compositions and their retention times in HPLC. Lysipressin (lysine vasopressin) was not detected in posterior pituitaries of two hippopotami and nine peccaries (less than 2% of arginine vasopressin in molar ratios). Among the suborder Suiformes of Artiodactyla, the families Hippopotamidae and Tayassuidae do not seem to possess lysipressin, in contrast to the family Suidae in which the pig has lysipressin in place of arginine vasopressin.
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Abstract
Neurohypophysial hormones and neurophysins are derived from common precursors processed during the axonal transport from the hypothalamus to the neurohypophysis. Two neurohormones, an oxytocin-like and a vasopressin-like, on one hand, two neurophysins, termed VLDV-and MSEL-neurophysins according to residues in positions 2, 3, 6 and 7, on the other, are usually found in vertebrate species. In contrast to placental mammals that have oxytocin and arginine vasopressin, marsupials have undergone a peculiar evolution. Two pressor peptides, lysipressin and vasopressin for American species, lysipressin and phenylpressin for Australian macropods, have been identified in individual glands and it is assumed that the primordial vasopressin gene has been duplicated in these lineages. On the other hand, the reptilian mesotocin is still present in Australian species instead of the mammalian oxytocin, while the North American opossum has both hormones and South American opossums have only oxytocin. The neurophysin domain of each precursor is encoded by 3 exons and different evolutionary rates have been found for the 3 corresponding parts of the protein. The central parts, encoded by the central exons, are evolutionarily very stable and nearly identical in the 2 neurophysins of a given species. Recurrent gene conversions have apparently linked the evolutions of the 2 precursor lineages. In mammals, the 3-domain precursor of vasopressin is processed in 2 stages: a first cleavage splitting off vasopressin and a second cleavage separating MSEL-neurophysin from copeptin. Two distinct enzymatic systems seem to be involved in these cleavages. Processing is usually complete at the level of the neurohypophysis, but an intermediate precursor encompassing MSEL -neurophysin and copeptin linked by an arginine residue has been characterized in guinea pig. In vitro processing of this intermediate through trypsin--Sepharose reveals cleavages only in the interdomain region. In non-mammalian tetrapods, such as birds and amphibians, mesotocin and vasotocin are associated with neurophysins in precursors similar to those found in mammals. However, processing of the vasotocin precursor seems to be different from the processing of the vasopressin precursor, with a single cleavage leading to the hormone release.
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Neurohypophysial hormones of the 1-month-old bovine fetus: absence of vasotocin during mammal development. FEBS Lett 1988; 234:345-8. [PMID: 3391278 DOI: 10.1016/0014-5793(88)80113-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The neurohypophysial hormones of the 1-month-old bovine fetus have been identified by their positions in ion-exchange chromatography and their retention times in high-pressure reverse-phase partition chromatography. Arginine vasopressin and oxytocin have been recognized. The molar ratio vasopressin/oxytocin in neurohypophysis is about 6 in the 1-month-old fetus compared with 4 in the 3-month-old fetus, 2.7 in the 7-month-old fetus and 1 in the adult. Vasotocin is virtually absent even in the early fetus (less than 0.1% of arginine vasopressin). The occurrence of a vasotocin gene expressed in the fetus but silent in the adult appears unlikely.
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Dual duplication of neurohypophysial hormones in an Australian marsupial: mesotocin, oxytocin, lysine vasopressin and arginine vasopressin in a single gland of the northern bandicoot (Isoodon macrourus). Biochem Biophys Res Commun 1988; 154:346-50. [PMID: 3395337 DOI: 10.1016/0006-291x(88)90691-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neurohypophysial hormones of an Australian marsupial, the Northern bandicoot (Isoodon macrourus), have been identified by their retention times in high-pressure reverse-phase liquid chromatography using two solvent systems and by their molar pressor or uterotonic activities. Two pressor peptides, arginine vasopressin and lysipressin, and two uterotonic peptides, mesotocin and oxytocin, have been characterized. Because mesotocin and arginine vasopressin have been identified in three other Australian marsupial families, it is assumed that a duplication of each ancestral gene occurred in Peramelidae and subsequent mutations in one copy led to the additional oxytocin and lysipressin. A similar dual duplication of neurohypophysial hormones has previously been discovered in the North-American opossum (Didelphis virginiana) so that the duplication propensity seems peculiar to marsupials in contrast to placental mammals.
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An amphibian two-domain 'big' neurophysin: conformational homology with the mammalian MSEL-neurophysin/copeptin intermediate precursor shown by trypsin-sepharose proteolysis. FEBS Lett 1988; 230:77-80. [PMID: 3258254 DOI: 10.1016/0014-5793(88)80645-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A 'big' frog (Rana esculenta) neurophysin, encompassing sequences homologous to mammalian MSEL-neurophysin and copeptin, has been passed through a trypsin-Sepharose column in order to compare its conformation with that of the two-domain intermediate precursor isolated from guinea pig. Whereas the polypeptide possesses 8 arginine residues, only two cleavages were observed located in a putative inter-domain sequence (at Arg-94 and Arg-114). Because free vasotocin has been isolated from the frog, it is assumed that pro-vasotocin has a three-domain conformation similar to that of pro-vasopressin but processing in amphibians involves only one step rather than two steps as in mammals.
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Isolation of neurosecretory granules containing vasopressin and MSEL-neurophysin from guinea pig neurointermediate pituitary. Neuropeptides 1988; 11:33-7. [PMID: 3368035 DOI: 10.1016/0143-4179(88)90025-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neurosecretory granules have been isolated from rat and guinea pig neurointermediate pituitaries and their contents have been analyzed by reverse-phase high-pressure liquid chromatography and polyacrylamide gel electrophoresis. Granule components have been compared with synthetic neurohypophysial hormones and chemically characterized neurophysins. In rat granules, oxytocin, arginine vasopressin and MSEL- and VLDV-neurophysins have been identified. In isolated guinea pig granules, only arginine vasopressin and mature MSEL-neurophysin have been found. From these results it can be concluded that both the "dibasic" cleavage between vasopressin and MSEL-neurophysin and the "monobasic" cleavage between MSEL-neurophysin and copeptin occur within the granule compartment. Previous isolation from frozen guinea pig glands of a partially processed precursor encompassing MSEL-neurophysin and copeptin suggests a two-step processing of the three-domain vasopressin precursor, each involving a distinct enzymic system.
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One-step processing of the amphibian vasotocin precursor: structure of a frog (Rana esculenta) "big" neurophysin. Biochem Biophys Res Commun 1987; 149:538-44. [PMID: 3501288 DOI: 10.1016/0006-291x(87)90401-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Vasotocin-associated neurophysin (MSEL-neurophysin) from the frog Rana esculenta has been isolated and sequenced through tryptic and staphylococcal proteinase peptides and cyanogen bromide fragments. This protein appears homologous to the mammalian vasopressin-associated neurophysin with a C-terminal glycopeptide extension homologous to the mammalian copeptin. In contrast to the two-step processing of mammalian vasopressin/MSEL-neurophysin/copeptin precursor, a single cleavage is therefore involved in the processing of the amphibian vasotocin/neurophysin precursor. It appears that the physiological release of the vasopressin-like hormone from the N-terminal end of the protein precursor is not dependent upon a previous trimming of the C-terminal copeptin-like moiety.
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Guinea pig MSEL-neurophysin. Sequence comparison of eight mammalian MSEL-neurophysins. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1987; 30:676-82. [PMID: 3436704 DOI: 10.1111/j.1399-3011.1987.tb03379.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The amino acid sequence of guinea pig MSEL-neurophysin has been determined using tryptic peptides derived from the performic acid-oxidized protein and staphylococcal proteinase peptides obtained from the reduced-carboxamidomethylated neurophysin. Guinea pig MSEL-neurophysin consists of a 93-residue polypeptide chain that shows 12 substitutions and 2 deletions when compared to bovine MSEL-neurophysin. It displays the highest number of variations among known mammalian MSEL-neurophysins. These variations are mainly found in the C-terminal region (residues 88-93). Moreover guinea pig MSEL-neurophysin, like rat homologous protein, exhibits substitutions in positions 2, 5, 29 and 81 and lacks an arginine in the penultimate position. Comparison between eight mammalian MSEL-neurophysins reveals a highly conserved region (residues 1 to 88) and a hypervariable region (residues 89 to 93/95). On the other hand the eight species examined are endowed with arginine vasopressin except pig, which has a lysine vasopressin. In the vasopressin-MSEL-neurophysin precursor, the hormonal moiety and the MSEL region of neurophysin (residues 1-9) are encoded by a common exon in ox, rat and man; it can be concluded that this exon is evolutionarily conservative in contrast to the one encoding the C-terminal region of MSEL-neurophysin.
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Evolution of marsupials traced by their neurohypophyseal hormones: microidentification of mesotocin and arginine vasopressin in two Australian families, Dasyuridae and Phascolarctidae. Gen Comp Endocrinol 1987; 67:399-408. [PMID: 3666414 DOI: 10.1016/0016-6480(87)90195-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Neurohypophyseal hormones of two species belonging to the family Dasyuridae, namely Dasyurus viverrinus (Eastern native cat) and Dasyuroides byrnei (Kowari), and of the single living member of the family Phascolarctidae, Phascolarctos cinereus (Koala) have been isolated and characterized by their retention times in high-pressure reverse-phase partition chromatography and either amino acid composition or amino acid sequence through a gas-phase microsequencer. Mesotocin and arginine vasopressin have been identified in the three species. The same hormones have previously been found in a species belonging to the family Phalangeridae, Trichosurus vulpecula (brush-tailed possum), whereas in five species of Macropodidae, mesotocin, lysipressin, and phenypressin have been characterized. Because the four Australian marsupial families examined up to now possess mesotocin and at least a vasopressin-like peptide, it is assumed that the primitive marsupial settler in Australia was endowed with mesotocin and arginine vasopressin.
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Gene conversion in avian mesotocin and vasotocin genes: a recurrent mechanism linking two neurohypophysial precursor lineages? Biosci Rep 1987; 7:631-6. [PMID: 3427215 DOI: 10.1007/bf01127675] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Amino acid sequences of the first half of MSEL- and VLDV-neurophysins from goose and chicken have been determined. Identical substitutions in positions 17, 18, 35, 36 and 41 of both neurophysins of a given species when compared with their mammalian counterparts suggest a gene conversion between vasotocin--MSEL-neurophysin and mesotocin--VLDV-neurophysin genes. This event, which has already been observed for three mammalian species, seems recurrent and would link the evolution of the two neurohypophysial hormone precursors.
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Conformation limited proteolysis in the common neurophysin-copeptin precursor shown by trypsin-sepharose chromatographic proteolysis. FEBS Lett 1987; 217:180-3. [PMID: 3595848 DOI: 10.1016/0014-5793(87)80659-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The guinea pig two-domain precursor of MSEL-neurophysin and copeptin has been passed through a trypsin-Sepharose column in order to mimic the enzyme processing by a membrane-bound endopeptidase. Only two cleavages were observed located in the inter-domain sequence (at Arg-94 and Arg-98), in contrast to several additional cleavages found when free neurophysin or copeptin is subjected to soluble trypsin. Because the physiological maturation involves a single cleavage at Arg-94, both local accessibility in the precursor and narrow specificity of the enzyme are implied in the processing.
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Ontogeny of the bovine neurohypophysial hormone precursors. III. Identification of neurohormones, neurophysins and copeptin in the early bovine fetus. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1987; 29:604-12. [PMID: 3610475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Neurohypophysial hormone precursors are small proteins processed into several fragments during axonal transport from hypothalamus to neurohypophysis. From 3-month-old fetal bovine pituitaries the three fragments of vasopressin precursor, arginine vasopressin, MSEL-neurophysin and copeptin, and the two fragments of oxytocin precursor, oxytocin and VLDV-neurophysin, have been isolated and characterized. These polypeptides are identical to those previously identified in the late fetus (7-9 months old) and in the adult. It is concluded that the same genes are expressed during fetal and adult lives, the vasopressin gene appearing roughly four times more active than the oxytocin gene in the early fetus. Vasotocin, mesotocin and additional neurophysin have not been detected in the early fetus.
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Abstract
Guinea pig neurohypophysial hormones have been purified by two procedures, one involving molecular sieving and paper chromatoelectrophoresis, the other high-pressure reverse-phase liquid chromatography. Arginine vasopressin and oxytocin have been identified by their amino acid compositions and their retention times in HPLC determined through their biological properties. No partially processed precursor, including a neurohormone and a neurophysin, has been detected. Because the cleavage of the three-domain vasopressin-neurophysin-copeptin precursor is apparently complete between the first two domains, whereas it is not between the second and the third, it is supposed that two distinct enzymic systems are involved in the processing.
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