Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0009443 (cold)
 92,137 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Estradiol and testosterone both lowered endogenous liver glycogen and at 20-fold higher doses impaired triamcinolone acetonide mediated glyconeogenesis in adult adrenalectomized male rats. Neither steroid influenced liver tyrosine transaminase although tryptophan pyrrolase activity was depressed by testosterone. Progesterone increased liver tryptophan pyrrolase but did not influence other parameters. Cortexolone did not alter either of these processes whereas cortisol induced both enzymes and, at much higher dose levels, gluconeogenesis. Binding of 3H-triamcinolone acetonide to its cytoplasmic receptor in vitro was left unaffected in presence of 20-fold greater concentration of either sex steroid but almost totally abolished by cold, homologous molecules. Similar results were obtained by 3H-cortisol except that estradiol partially competed for 3H-cortisol binding sites even at 20-fold greater concentrations of cold estradiol. Separation on DEAE-cellulose-52 and Ultrogel 44 columns revealed binding of all steroids to macromolecules of comparable physicochemical properties although the ratios of binding to the various subpopulations of the receptor were a function of the steroid in question. These results are discussed in terms of sex steroid binding to different moieties of a complex, heterogeneous, polymorphic protein rather than inhibition of binding to the active configuration acquired in presence of an inducer.
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PMID:Search for antiglucocorticoid activity in rat liver in vivo. 4 49

A substance has been purified to apparent homogeneity from rat liver which, as previously reported (Dunaway, G. A., Jr., and Segal, H. L. (1974) Biochem. Biophys. Res. Commun. 56, 689-696), specifically stabilizes the major liver isozyme of phosphofructokinase (PFK-L2) against thermal inactivation and whose level in vivo changes in parallel with and in precedence to that of the enzyme. Molecular weight determinations gave values around 3,500. Evidence for the peptide nature of the factor includes its correspondence with ninhydrin-positive material on gel filtration and paper electrophoresis and its susceptibility to pronase. Electrophoretic behavior indicated at least one free amino group and several carboxyl groups. Amino acid analysis of the peptide yielded only glutamate, glycine, and half-cystine, in equimolar amounts. However, neither GSH nor GSSG have PFK-L2-stabilizing activity. No free sulfhydryl groups were present. Chemical analysis for tryptophan was also negative. The ultraviolet spectrum confirmed the absence of aromatic amino acids. The spectrum exhibited a characteristic peptide peak at 190 nm with no absorbance beyond 240 nm. The factor is unstable to storage in the cold except in the presence of glucose or dithiothreitol. Sucrose, fructose, and GSH were ineffective in this regard. It was slowly denatured by heat or reduced pH even in the presence of glucose. The factor was induced in fasted animals specifically by glucose, of the nutrients tested, and in diabetic animals by insulin. Induction by both glucose and insulin was blocked by cycloheximide and actinomycin. The time course of the glucose induction was the more rapid of the two with a marked overshoot to 3 times normal levels at 12 hours. Increased levels of the factor preceded the increased levels of PFK-L2 brought about by glucose or insulin administration. Native PFK-L2 was inactivated by lysosomal extracts, and this inactivation was strongly inhibited by the peptide factor. These results are in accord with the proposal that the peptide plays a role in regulating PFK-L2 turnover in vivo. The factor also activated the phosphofructokinase-catalyzed reaction by promoting fructose-6-P binding. This effect is analogous to that of AMP on the kinetics of the reaction; however, the factor effect was additive to that of AMP, and the factor did not reverse inhibition by excess ATP as does AMP. We postulate that the stabilizing factor affects an equilibrium between PFK-L2 conformers in favor of one more resistant to lysosomal and thermal inactivation and with greater affinity for fructose-6-P.
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PMID:Purification and physiological role of a peptide stabilizing factor of rat liver phosphofructokinase. 13 Nov 26

Gluconeogenic conditions, such as administration of triamcinolone or alloxan diabetes, cause the following changes in the molecular structure and properties of rabbit liver fructose 1,6-bisphosphatase (D-fructose-1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11): (1) the appearance of traces (about 10%) of a lighter subunit; (2) loss of tryptophan from all of the subunits, including those that show no apparent change in molecular weight; (3) increase in requirement for the positive allosteric effector, histidine; (4) increase in amount of enzyme, but not its specific activity. These changes are identical to those induced by cold or fasting, and are related to increased activities of lysosomal proteases. The results suggest that lysosomes may act as mediators of gluconeogenic stimuli.
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PMID:Hormonal effects on structure and catalytic properties of fructose 1,6-bisphosphatase. 17 48

1. A large-scale purification of the nitrogenase components from Azotobacter chroococcum yielded two non-haem iron proteins, both of which were necessary for nitrogenase activity and each had a specific activity of approximately 2000 +/- 300 nmol of acetylene reduced/mg protein per min in the presence of sautrating amounts of the other. This procedure freed the Mo-Fe protein from a protein contaminant which had an electron paramagnetic resonance signal at g = 1.94. 2. Both proteins were purified to homogeneity as determined by disc gel electrophoresis and ultracentrifugal analysis. Both proteins were oxygen-sensitive but not cold-labile. Ultracentrifugal analysis indicated that both proteins dissociated to a slight degree at concentrations below 2 mg/ml. 3. The larger of the two proteins had a molecular weight of 227 000 and contained 1.9 +/- 0.3 atoms of Mo, 23 +/- 2 atoms of Fe, 20 +/- 2 acid-labile sulphide and 47 tryptophan residues/mol. The protein consists of 4 subunits of mol. wt 60 000 (approx.). The reduced protein showed electron paramagmetic resonance signals at g = 4.29, 3.65 and 2.013 but not in the area of g = 5 to 6. Upon oxidation abosrbance increased throughout the visible region of the ultraviolet visible spectrum, with a maximum difference between oxidised and reduced protein occurring at 430 nm. 4. The smaller protein had a molecular weight of 64 000 and contained 4 g-atoms of Fe and 4 acid-labile sulphide groups/mol but no tryptophan. It had two subunits of mol. wt 30 800. The reduced protein showed electron paramagnetic resonance signhe protein retained almost full activity after oxidation with phenazine methosulphate. The ultraviolet visible spectrum of oxidised protein was clearly different from that of the oxygen-inactivated protein: it had a sharp peak at 269 nm and a broad absorbance between 340 and 470 nm with a maximum difference between oxidised and reduced forms at 430 nm. Oxygen-inactivated protein showed a sharp peak at 277.5 nm and broad peaks from 305 to 360, 400 to 425 and 435 to 475 nm. 5. Amino acid analyses of both proteins showed that most common amino acids were present with a preponderance of acidic residues. Analyses of compositional relatedness showed that the nitrogenase proteins from A. chroococcum were most closely related to those from A. vinelandii and least so to those from Clostridium pasteurianum.
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PMID:Nitrogenase from Azotobacter chroococcum. Purification and properties of the component proteins. 17 45

To study the effects of preinduced hypothermia on the physiological and thermoregulatory responses to exercise in the heat rats were intravenously administered either 100 micrograms of chlorpromazine (CPZ) or 200 mg/kg of L-tryptophan (L-Trp) under restraint in a cold (4 degrees C) environment. When rectal temperatures (Tre) reached 32-33 degrees C the rats were removed to a hot environment (35 degrees C) where they ran on a level treadmill (9.14 m/min) to hyperthermic exhaustion (Tre, 42.5-43 degrees C). Both CPZ and L-trp hypothermia was effective in increasing significantly (P less than 0.001) the time to hyperthermic exhaustion. However, the maximal Tre and skin temperatures (Tsk) attained were unaffected by either treatment. When the rats exercised on the treadmill, increments (degrees C/min) in Tre and Tsk were significantly (P less than 0.02, minimal) greater for the initially hypothermic animals compared to normothermic controls. Cooling rates were unaffected by either treatment. We concluded from these studies that, although preinduced hypothermia is extremely effective in prolonging the time to hyperthermic exhaustion, no additional beneficial thermoregulatory responses accrued as a result of this treatment.
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PMID:Hypothermia induced by chlorpromazine or L-tryptophan: effects on treadmill performance in the heat. 51 90

The acrylamide-quenching patterns of the intrinsic tryptophan fluorescence of six cold-soluble monoclonal immunoglobulin M (IgM) and two monoclonal IgM proteins possessing cryoglobulin properties (abnormal cold insolubility) have been compared. Static and dynamic components of quenching have been resolved by a modified form of the Stern-Volmer relationship. The unusual observation of static quenching seen with the multitryptophan containing IgM is determined to be a consequence of essentially homogeneous indole fluorescence arising from conserved tryptophan residues within each homologous immunoglobulin domain. Although the static component of the quenching of the two IgM cryoimmunoglobulins examined is similar to that of the non-cryoimmunoglobulin, IgM, some of the cryoglobulin's tryptophan residues appear to be more kinetically exposed to acrylamide than the tryptophans in the non-cryoglobulin IgM. An unusually large negative entropy of activation observed for the quenching process of both cryoimmunoglobulins suggests some abnormality in the dynamic (flexibility) properties of these proteins.
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PMID:Investigations of the molecular basis for the temperature-dependent insolubility of cryoglobulins. VI. Quenching by acrylamide of the intrinsic tryptophan fluorescence of cryoglobulin and non-cryoglobulin IgM proteins. 66 17

It has been shown previously that the binding of pyridoxal 5'-phosphate to Escherichia coli K 12 tryptophanase brings about an important conformational change of the protein. The way in which this structural change is transmitted from holoprotomers to apoprotomers is investigated here, using hybrid molecules (between apoprotomers and irreversibly saturated holoprotomers). It is shown that the binding of two or three coenzyme molecules per tetramer stabilizes the whole molecule against thermal inactivation and cold-induced dissociation. The change in conformation induced on an apoprotomer by the proximity of three holoprotomers is described, using three structural probes: the kinetics of binding of the cofactor and of 5'-phosphopyridoxyl-tryptophan (an analog of an intermediate in the catalytic reaction), and the reactivity of the essential cysteines. The kinetic anticooperatively in the binding of pyridoxal 5'-phosphate is confirmed, some of its parameters are determined, and its mechanism is interpreted in relation to the coupling between the protomers.
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PMID:Structural and functional interdependence of the protomers of Escherichia coli K 12 tryptophanase during binding of pyridoxal 5'-phosphate. 77 Apr 72

1. Investigations were designed to identify the proteins which characterize the ameloblast phenotype, and to determine to what extent these extracellular-matrix proteins were degraded as a function of enamel matrix mineralization and maturation. 2. The identification of enamel proteins was based on comparisons between the electrophoretic patterns of enamel-containing and non-enamel-containing matrix extracts isolated from specific regions within 26-day embryonic New Zealand White rabbit incisor and molar tooth organs. 3. Since enamel proteins become mineralized on secretion, matrix specimens were demineralized in cold 5% (w/v) trichloroacetic acid, extracted with buffered 6M-urea and reduced with mercaptoethanol, and then the solubilized proteins were fractionated by urea/polyacrylamide-gel electrophoresis. 4. Three enamel-specific electrophoretic components were identified in newly secreted enamel-matrix specimens and this number increased as a function of mineralization and maturation. 5. Antibodies were prepared against embryonic rabbit extracellular matrix containing enamel. Comparison between immunoelectrophoretic patterns demonstrated that two of the three enamel components were antigenic. 6. Polyacrylamide-gel electrophoresis in sodium dodecyl sulphate was used to identify four enamel proteins of mol.wts. (1) 65 000 (2) 58000 (3) 22 000 and (4) 20 000, localized within enamel matrix. Enamel proteins (1) and (3) were phosphorylated, whereas (2) and (4) did not contain detectable phosphate. Labelled proline, leucine, tryptophan and glucosamine were incorporated into each of the four enamel proteins extracted from tooth explants incubated in the presence of radioactive precursors for 6 h. Whereas four proteins were identified in newly secreted enamel matrix, the concentrations of high-molecular-weight proteins (1) and (2) were found to decrease and the number (greater than 10) and concentration of low-molecular-weight polypeptides increased as a function of advanced enamel-matrix mineralization and maturation.
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PMID:Identification of four extracellular-matrix enamel proteins during embryonic-rabbit tooth-organ development. 88 Feb 19

Magnetic-resonance techniques are used to refine the model of the combining site of the Fv fragment of the dinitrophenyl-binding mouse myeloma protein MOPC 315 constructed by Padlan, Davies, Pecht, Givol & Wright (1976) (Cold Spring Harbor Symp. Quant. Biol.41, in the press). Light-absorption studies indicate a dinitrophenyl-tryptophan interaction in the Fv fragment of the type occurring in free solution. The Dnp-aspartate-tryptophan complex is therefore used as a starting point for the n.m.r. (nuclear-magnetic-resonance) analysis of the dinitrophenyl-Fv fragment interaction. Ring-current calculations are used to determine the geometry of the complex. The specificity of complex-formation between dinitrophenyl and tryptophan is confirmed by the lack of ring-current shifts of the dinitrophenyl resonances when tryptophan is replaced by any other aromatic amino acid. Proton n.m.r. difference spectra (at 270MHz), resulting from the addition of a variety of haptens to the Fv fragment, show that the combining site is highly aromatic in nature. Calculations on the basis of ring-current shifts define the geometry of the combining site, which involves a dinitrophenyl ring in van der Waals contact with four aromatic amino acid residues on the protein. The observation of a nuclear Overhauser effect on the H((3)) resonance of the dinitrophenyl ring provides additional constraints on the relative geometry of the H((3)) proton and an aromatic amino acid residue on the Fv fragment. The specificity of the Fv fragment for dinitrophenyl ligands arises from a stacking interaction of the dinitrophenyl ring with tryptophan-93(L), in an ;aromatic box' of essentially tryptophan-93(L), phenylalanine-34(H) and tyrosine-34(L); asparagine-36(L) and tyrosine-34(L) also contribute by forming hydrogen bonds with the nitro groups on the dinitrophenyl ring. The n.m.r. results also confirm that the antibody-hapten reaction may be visualized as a single encounter step. An Appendix shows the method of calculation of ring currents for the four aromatic amino acids and their use in calculating structures.
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PMID:The combining site of the dinitrophenyl-binding immunoglobulin A myeloma protein MOPC 315. 92 44

1. The preliminary phytochemical screening of the two seeds established the presence of carbohydrates and/or glycosides, flavnoids, unsaturated sterols and/or triterpenes, saponins, trypsin inhibitors and haemagglutinins. In addition, it established the absence of cardenolides, tannins, alkaloids and oxidase enzyme. 2. Certain pharmacopoeial constants, including moisture, ash, acid-insoluble ash, water-soluble ash and crude fibre were determined. 3. The two seeds were subjected to successive extractions with different organic solvents such as petroleum ether (50-70 degrees C), diethyl ether, chloroform and ethyl alcohol. The successive yields of extractives were determined. Examination of the crude extracts showed that petroleum ether extract contained sterols and/or triterpenes, while ether, chloroform, and ethyl alcohol extracts contained reducing substances. 4. General analysis of the two seeds for proteins, fats, carbohydrates, fibre and ash contents were carried out and the results were given in g/100 g dry seeds. Pigeon pea contained 25.2 g protein, 170 mg calcium and 8.9 mg iron. The protein content of kidney bean was 23 g, while calcium and iron contents were 134 mg and 8.02 mg respectively. 5. Extractions of the proteins using different solvents such as cold water, hot water, saline buffer pH 7 and sodium hydroxide was the best extractant. 6. The amino-acid content of the two seeds, whether raw or cooked, showed that they were deficient in methionine, cystine and tryptophan. Other essential amino acids were present in amounts higher than that given by the FAO provisional pattern. 7. Cooking the seeds by the popular methods used in the country resulted in an increase in the amounts of the amino acids, threonine, leucine and isoleucine, while the other amino acids present remained unchanged or decreased. It was also observed that cooking the seeds destroyed the trypsin inhibitors and haemagglutinins found in the two seeds.
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PMID:Phytochemical and nutritional studies on pigeon pea and kidney bean cultivated in Egypt. 96 10


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