Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A pancreatic polypeptide with some hormonal properties has been purified from chicken and turkey pancreas using acid-ethanol extraction, gel filtration and anion-exchange chromatography. The material has been crystallised. The crystals are monoclinic with space group C2. Preliminary isomorphous replacement experiments have so far provided a single-site derivative with Hg(NO3)2. A low-resolution electron density map phased with this derivative using anomalous scattering considered together with Patterson function calculations suggest that the molecules are partly helical and are arranged as a compact dimer about the crystallographic two-fold axis. The structure and association of these molecules are compared with those of insulin and glucagon, pancreatic protein and polypeptide hormones respectively, which have been studied in great detail.
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PMID:Purification, crystallisation and preliminary X-ray studies on avian pancreatic polypeptide. 91 91

1. An anionic and a cationic chymotrypsin (EC 3.4.21.1) were isolated from the pancreas glands of the moose (Alces alces) and elk (Cervus elaphus). The A and B chymotrypsins from each species were purified to homogeneity by (NH4)2SO4 fractionation, affinity chromatography on 4-phenylbutylamine-Sepharose and ion-exchange chromatography on DEAE- and CM-cellulose. 2. The molecular weight and pH optimum of each chymotrypsin were similar to those of the corresponding ox A and B chymotrypsins. 3. The substrate specificities of the chymotrypsins were investigated by digestion of glucagon and the oxidized B chain of insulin. The primary specificity of each chymotrypsin for aromatic amino acid residues was further established by determining the Km and kcat for the hydrolysis of a number of synthetic amino acid ester substrates. 4. The amino acid composition and total number of residues of moose and elk chymotrypsin A were similar to those of ox chymotrypsin A. An even greater similarity was observed among the B chymotrypsins of the three species. 5. The A chymotrypsins of moose and elk were fragmented to their constituent 'A', 'B' and 'C' polypeptide chains by succinylation (3-carboxypropionylation), reduction and alkylation of the native enzymes. In each case, the two major chains ('B' and 'C') were separated and isolated. By comparison of the amino acid compositions of moose, elk and oxy 'B' and 'C' chains, a greater difference was observed among the three A chymotrypsins than was suggested by the amino acid compositions of the native enzymes alone. 6. Peptides were isolated from the disulphide bridge and active-site regions of the A and B chymotrypsins of moose and elk by diagonal peptide-'mapping' techniques. From the amino acid compositions of the isolated peptides (assuming maximum homology) and from a comparison of diagonal peptide 'maps', there was established a high degree of primary-structure identity among the mooae, elk and ox chymotrypsins. Tentative sequences were deduced for the peptides isolated by diagonal peptide 'mapping'. 7. Details of the isolation procedures of the moose and elk chymotrypsins A and B and the amino acid analyses of some peptides obtained by diagonal peptide 'mapping' have been deposited as Supplementary Publication SUP 50064 (27 pages) at the British Library Lending Division, Boston Spa, Wetherby, W. Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1976) 153, 5.
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PMID:Chymotrypsins from the deer (Cervidae) family. Isolation, partial characterization and primary-structure studies of chymotrypsins A and B from both moose (Alces alces) and elk (Cervus elaphus) pancreas. 94 18

Gastrointestinal hormones are considered to be those that are formed in the gastrointestinal tract and there, in physiological concentrations, develop their effects on motility, secretion, trophism, bloodflow and absorption. Structural analysis, synthesis or a high degree of purity after extraction, and its exact demonstration by means of a useful radioimmunoassay, form the basis for the establishment of a polypeptide as a gastrointestinal hormone. To this category belong, at the present time, gastrin, cholecystokinin-pancreozymin (CCK-PZ) and secretin. GIP, VIP, motilin, glucagon and somatostatin are considered likely candidates. The substances gastrin and CCK-PZ, which are structurally related and have a predominantly stimulating effect, and the structurally dissimilar motilin, contrast with the partially or totally inhibiting hormones of the glucagon family, namely, secretin, VIP, glucagon-enteroglucagon, GIP and somatostatin. By the combined action of these hormones with one another and with the autonomic nervous system, the digestive processes are regulated. Disturbances in the formation of these hormones, in particular an overproduction, give rise to disease syndromes that can now be diagnosed and, in part, treated by surgery. The therapeutic application of gastrointestinal hormones has now also become a possibility.
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PMID:[Gastrointestinal hormones]. 96 Sep 54

Eighteen endocrine pancreatic tumors were examined for the occurrence of cells producing insulin, glucagon, gastrin, human pancreatic polypeptide (HPP), and vasoactive intestinal polypeptide (VIP) and for A1 cells. More than half of the tumors were mixed, i.e., they contained more than one type of hormone-producing cell. The clinical symptoms were attributable only to one of the hormones produced by the mixed tumors. Three of four tumors causing the watery diarrhea syndrome contained both VIP and HPP cells. In one such tumor there was a strong predominance of HPP cells; the serum HPP levels of this patient were a thousandfold elevated, whereas her VIP levels were within the normal range. Several lines of evidence point to HPP as a possible agent causing the watery diarrhea syndrome. In many of our patients, HPP cells hyperplasia was present in the extratumoral pancreas. Such hyperplasia may give rise to the raised serum HPP levels seen in many patients having endocrine pancreatic tumors.
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PMID:Occurrence of human pancreatic polypeptide in pancreatic endocrine tumors. Possible implication in the watery diarrhea syndrome. 99 36

The effect of glucagon on hepatic protein systhesis and proteolysis has been investigated. The intraperitoneal administration of 200 mug of glucagon produced an increase of the polypeptide chains completion time which was maximal 5 min after its administration and approached control values at 20 min. The increase of the polypeptides chains completion time observed at 5 min after the hormone administration represents a 38% inhibition of the hepatic protein synthetic rate. When glucagon was continuously supplied by intravascular infusion, maximal inhibition was attained throughout the experiment. This inhibition of protein synthesis brought about by glucagon was accompanied by an increase in the polyribosomal state of aggregation, indicating that the hormone acts mainly if not exclusively, on the elongation or termination step, or both. The administration of glucagon produced also a progressive increase in the hepatic valine concentration. This increase could not be accounted for the the decrease in plasma valine levels, suggesting that the rise in haptic valine concentration is an expression of hepatic proteolysis rather than the result of an accelerated transport of amino acids across the hepatocyte plasma membrane. The different time sequence in the glucagon-induced effects of protein synthesis and proteolysis suggests that both effects are independent and probably mediated by different mechanisms.
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PMID:Role of glucagon on the control of hepatic protein synthesis and degradation in the rat in vivo. 100 12

1. A technique for indirectly labelling antibodies to polypeptide hormones, by combining them with radioactively labelled anti-(immunoglobulin G) is described. (a) 125I-labelled anti-(rabbit immunoglobulin G) and anti-(guinea-pig immunoglobulin G) antibodies with high specific radioactivity were prepared after purification of the antibodies on immunoadsorbents containing the respective antigens. (b) Rabbit immunoglobulin G antibodies to human growth hormone, porcine glucagon and guinea-pig immunoglobulin G antibodies to bovine insulin and bovine parathyroid hormone were combined with immunoadsorbents containing the respective polypeptide hormone antigen. (c) The immunoglobulin G antibodies to the polypeptide hormones were reacted with 125-I-labelled anti-(immunoglobulin G) antibodies directed against the appropriate species of immunoglobulin G,and the anti-hormone antibodies were combined with the hormone-containing immunoadsorbent. (d) 125I-labelled anti-(immunoglobulin G) antibodies and anti-hormone antibodies were simultaneously eluted from the hormone-containing immunoadsorbent by dilute HCl, pH 2.0. After elution the anti-(immunoglobulin G) antibodies and antihormone antibodies were allowed to recombine at pH 8.0 and 4 degrees C. 2. The resultant immunoglobulin G-anti-immunoglobulin G complex was used in immunoradiometric (labelled antibody) and two-site assays of the respective polypeptide hormone. 3. By using these immunoassays, concentrations down to 90pg of human growth hormone/ml, 100 pg of bovine insulin/ml, 80 pg of bovine parathyroid hormone/ml and 150 pg of glucagon/ml were readily detected. Assays of human plasma for growth hormone and insulin by these methods showed good agreement with results obtained by using a directly 125I-labelled anti-hormone antibody in an immunoradiometric assay of human growth hormone or by radioimmunoassay of human insulin. 4. The method described allows immunoradiometric or two-site assays to be performed starting with as little as 450 ng of polypeptide hormone-antibody protein. An additional advantage of the method is that a single iodination of the readily available antibodies to immunoglobulin G allows the establishemnt of several polypeptide hormone assays
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PMID:Immunoassay of serum polypeptide hormones by using 125I-labelled anti(-immunoglobulin G) antibodies. 108 Apr 19

Evidence is presented that proglucagon from anglefish islets is a single chain polypeptide with 78 amino acid residues and that the glucagon portion of it is liberated after tryptic cleavage. The most striking characteristic in the conversion of the anglerfish proglucagon to glucagon is that the cleaved peptide bonds display enormous sensitivity toward trypsin. Thus, conversion of the prohormone to glucagon occurs very rapidly within 3-10 min with a 1:500-1:1000 molar ratio of enzyme to substrate. Further, trypic cleavage of the anglerfish glucagon requires higher concentrations of trypsin (molar ratio 1:25 enzyme to substrate) and longer incubation time. The behavior of proglucagon and glucagon toward trypsin shows striking similarities with the tryptic conversion of anglerfish proinsulin to insulin.
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PMID:Isolation and partial characterization of anglefish proglucagon. 109 38

It is proposed that glucagon, a polypeptide hormone, is delicately balanced between two major conformational states. Utilizing a new predictive model [Chou, P.Y., and Fasman, G.D. (1974), Biochemistry 13, 222] which considers all the conformational states in proteins (helix, beta sheet, random coil, and beta turns), the secondary structural regions of glucagon are computed herein. The conformational sensitivity of glucagon may be due to residues 19-27 which have both alpha-helical potential (mean value of Palpha = 1.19) as well as beta-sheet potential (mean value of Pbeta = 1.25). Two conformational states are predicted for glucagon. In predicted form (a), residues 5-10 form a beta-sheet region while residues 19-27 form an alpha-helical region (31% alpha, 21% beta) agreeing well with the circular dichroism (CD) spectra of glucagon. The similarity in the CD spectra of glucagon and insulin further suggests the presence of beta structure in glucagon, since X-ray analysis of insulin showed 24% beta sheet. In predicted form (b), both regions, residues 5-10 and residues 19-27, are beta sheets sheets (0% alpha, 52% beta) in agreement with the infrared spectral evidence that glucagon gels and fibrils have a predominant beta-sheet conformation. Since three reverse beta turns are predicted at residues 2-5, 10-13, and 15-18, glucagon may possess tertiary structure in agreement with viscosity and tritium-hydrogen exchange experiments. A proposal is offered concerning an induced alpha yields beta transition at residues 22-27 in glucagon during receptor site binding. Amino acid substitutions are proposed which should disrupt the beta sheets of glucagon with concomitant loss of biological activity. The experimental findings that glucagon aggregates to form dimers, trimers, and hexamers can be explained in terms of beta-sheet interactions as outlined in the present predictive model. Thus the conflicting conclusions of previous workers, concerning the conformation of glucagon in different environments, can be rationalized by the suggested conformational transition occurring within the molecule.
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PMID:The conformation of glucagon: predictions and consequences. 113 71

The effects of intravenous infusion of synthetic C-terminal octapeptide of cholecystokinin (OP-CCK) on concentrations of insulin and glucagon in peripheral venous plasma of conscious dogs were studied. Both hormones increased in response to 160 and 480 ng/kg/h of OP-CCK. The increases to 480 ng/kg/h were larger than those to 160 ng/kg/h. Peripheral venous concentrations of glucose and intestinal glucagon-like immunoreactivity were not altered by OP-CCK. OP-CCK, 160 ng/kg/h, did not enhance insulin and glucagon responses to intravenous infusion of amino acids. The results suggest that insulin- and glucagon-releasing actions of porcine cholecystokinin preparations should not be attributed entirely to gastric inhibtory polypeptide or other impurities contained in these preparations since the synthetic active fragment of cholecystokinin alone increases insulin and and glucagon concentrations in peripheral plasma.
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PMID:Effects of the octapeptide of cholecystokinin on insulin and glucagon secretion in the dog. 117 6

We have studied the effects of several porcine enteric polypeptide hormones on trout calcitonin (tCT) secretion in long-lived monolayer cultures of calcitonin-secreting (C-) cells derived from trout ultimobranchial glands. Gastrin, pancreozymin (CCK-PZ), glucagon, and secretin have dose-related stimulatory effects on tCT secretion; the distinct effects of secretin on tCT secretion are in contrast to its lack of CT secretagogue activity in some mammals. Synthetic peptide hormones and/or their structural analogs have variable secretory effects which correspond in general to the potency of the analogs for the well-recognized biological actions of these various peptide hormones in mammals. Although enteric peptide hormones are present in fish, their physiological role in the regulation of CT secretion has not been studied. These in vitro studies indicate a possible role for these hormones in the control of tCT secretion and support the concept that there are differences in the regulators of C-cell function in higher and lower vertebrates. In vitro studies of fish CT secretion are needed to establish the physiological significance of these in vitro studies of fish C-cell function.
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PMID:Calcitonin secretion in vitro. II. Regulatory effects of enteric mammalian polypeptide hormones on trout C-cell cultures. 126 21


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