| Records |
| Author |
Polverini, E.; Cugini, G.; Annoni, F.; Abbruzzetti, S.; Viappiani, C.; Gensch, T. |
| Title |
Molten globule formation in apomyoglobin monitored by the fluorescent probe Nile Red |
Type |
Journal Article |
| Year |
2006 |
Publication |
Biochemistry |
Abbreviated Journal |
Biochemistry |
| Volume |
45 |
Issue |
16 |
Pages |
5111-5121 |
| Keywords |
Animals; Apoproteins/*chemistry/*metabolism; Binding Sites; Computer Simulation; Fluorescent Dyes/analysis; Horses; Hydrogen-Ion Concentration; Models, Molecular; Myoglobin/*chemistry/*metabolism; Oxazines/*analysis/chemistry; Protein Binding; Protein Folding; Protein Structure, Tertiary |
| Abstract |
The interaction of nile red (NR) with apomyoglobin (ApoMb) in the native (pH 7) and molten globule (pH 4) states was investigated using experimental and computational methods. NR binds to hydrophobic locations in ApoMb with higher affinity (K(d) = 25 +/- 5 microM) in the native state than in the molten globule state (K(d) = 52 +/- 5 microM). In the molten globule state, NR is located in a more hydrophobic environment. The dye does not bind to the holoprotein, suggesting that the binding site is located at the heme pocket. In addition to monitoring steady-state properties, the fluorescence emission of NR is capable of tracking submillisecond, time-resolved structural rearrangements of the protein, induced by a nanosecond pH jump. Molecular dynamics simulations were run on ApoMb at neutral pH and at pH 4. The structure obtained for the molten globule state is consistent with the experimentally available structural data. The docking of NR with the crystal structure shows that the ligand binds into the binding pocket of the heme group, with an orientation bringing the planar ring system of NR to overlap with the position of two of the heme porphyrin rings in Mb. The docking of NR with the ApoMb structure at pH 4 shows that the dye binds to the heme pocket with a slightly less favorable binding energy, in keeping with the experimental K(d) value. Under these conditions, NR is positioned in a different orientation, reaching a more hydrophobic environment in agreement with the spectroscopic data. |
| Address |
Dipartimento di Fisica, Universita degli Studi di Parma, Viale G. P. Usberti 7/A, 43100 Parma, Italy |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0006-2960 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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Notes  |
PMID:16618100 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3763 |
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| Author |
Permyakov, S.E.; Khokhlova, T.I.; Nazipova, A.A.; Zhadan, A.P.; Morozova-Roche, L.A.; Permyakov, E.A. |
| Title |
Calcium-binding and temperature induced transitions in equine lysozyme: new insights from the pCa-temperature “phase diagrams” |
Type |
Journal Article |
| Year |
2006 |
Publication |
Proteins |
Abbreviated Journal |
Proteins |
| Volume |
65 |
Issue |
4 |
Pages |
984-998 |
| Keywords |
Animals; Apoproteins/chemistry/metabolism; Binding Sites; Calcium/chemistry/*metabolism; Cattle; Edetic Acid/metabolism; Horses/metabolism; Hydrogen-Ion Concentration; Lactalbumin/chemistry/metabolism; Muramidase/*chemistry/*metabolism; Protein Denaturation; Spectrometry, Fluorescence; *Temperature; Thermodynamics; Tryptophan/chemistry/metabolism |
| Abstract |
The most universal approach to the studies of metal binding properties of single-site metal binding proteins, i.e., construction of a “phase diagram” in coordinates of free metal ion concentration-temperature, has been applied to equine lysozyme (EQL). EQL has one relatively strong calcium binding site and shows two thermal transitions, but only one of them is Ca(2+)-dependent. It has been found that the Ca(2+)-dependent behavior of the low temperature thermal transition (I) of EQL can be adequately described based upon the simplest four-states scheme of metal- and temperature-induced structural changes in a protein. All thermodynamic parameters of this scheme were determined experimentally and used for construction of the EQL phase diagram in the pCa-temperature space. Comparison of the phase diagram with that for alpha-lactalbumin (alpha-LA), a close homologue of lysozyme, allows visualization of the differences in thermodynamic behavior of the two proteins. The thermal stability of apo-EQL (transition I) closely resembles that for apo-alpha-LA (mid-temperature 25 degrees C), while the thermal stabilities of their Ca(2+)-bound forms are almost indistinguishable. The native state of EQL has three orders of magnitude lower affinity for Ca(2+) in comparison with alpha-LA while its thermally unfolded state (after the I transition) has about one order lower (K = 15M(-1)) affinity for calcium. Circular dichroism studies of the apo-lysozyme state after the first thermal transition show that it shares common features with the molten globule state of alpha-LA. |
| Address |
Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1097-0134 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:17022083 |
Approved |
no |
| Call Number |
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Serial |
1858 |
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| Author |
Jablonska, E.M.; Ziolkowska, S.M.; Gill, J.; Szykula, R.; Faff, J. |
| Title |
Changes in some haematological and metabolic indices in young horses during the first year of jump-training |
Type |
Journal Article |
| Year |
1991 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
| Volume |
23 |
Issue |
4 |
Pages |
309-311 |
| Keywords |
Alanine Transaminase/blood; Animals; Bicarbonates/blood; Blood Glucose/analysis; Blood Proteins/analysis; Breeding; Carbon Dioxide/blood; Exercise Test/veterinary; Fatty Acids, Nonesterified/blood; Female; Fructose-Bisphosphate Aldolase/blood; Hematocrit/veterinary; Hemoglobins/analysis; Horses/*blood/metabolism; Hydrogen-Ion Concentration; Lactates/blood; Male; Oxygen/blood; *Physical Conditioning, Animal; Pyruvates/blood |
| Abstract |
Effects of an 18 min exercise test, on three separate occasions during a one year jump-training programme, was studied in seven horses. Determinations were carried out on venous blood for packed cell volume, haemoglobin, total protein, lactate and pyruvate, glucose, free fatty acids, insulin, glucagon, blood gases, bicarbonate, pH, aldolase, aspartate aminotransferase and alanine amino-transferase. Exercise caused a slight increase in lactate and pyruvate, total protein, aldolase, alanine aminotransferase, pO2, bicarbonate and pH. Glucose, free fatty acids and pCO2 levels decreased. Training caused no significant difference in these changes. However, during the year, increases in lactate and decreases in pH (resting levels) were observed. |
| Address |
Department of Vertebrate Animal Physiology, Warszawa, Poland |
| Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0425-1644 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:1915234 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3801 |
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| Author |
Wilson, M.T.; Ranson, R.J.; Masiakowski, P.; Czarnecka, E.; Brunori, M. |
| Title |
A kinetic study of the pH-dependent properties of the ferric undecapeptide of cytochrome c (microperoxidase) |
Type |
Journal Article |
| Year |
1977 |
Publication |
European Journal of Biochemistry / FEBS |
Abbreviated Journal |
Eur J Biochem |
| Volume |
77 |
Issue |
1 |
Pages |
193-199 |
| Keywords |
Animals; Cyanides; *Cytochrome c Group/metabolism; Ferric Compounds; Horses; Hydrogen-Ion Concentration; Imidazoles; Kinetics; Mathematics; Myocardium/enzymology; *Oligopeptides/metabolism; *Peptide Fragments/metabolism; Protein Binding; Spectrophotometry; Temperature |
| Abstract |
The ferric form of the haem undecapeptide, derived from horse cytochrome c by peptic digestion, undergoes at least three pH-induced transitions with pK values of 3.4, 5.8 and 7.6. Temperature-jump experiments suggest that the first of these is due to the binding of a deprotonated imidazole group to the feric iron while the second and third arise from the binding of the two available amino groups present (the alpha-NH2 of valine and the epsilon-NH2 of lysine). Molecular models indicate that steric retraints on the peptide dictate that these amino groups may only coordinate to iron atoms via intermolecular bonds, thus leading to the polymerization of the peptide. Cyanide binding studies are in agreement with these conclusions and also yield a value of 3.6 X 10(6) M-1 s-1 for the intrinsic combination constant of CN- anion with the haem. A model is proposed which describes the pH-dependent properties of the ferric undecapeptide. |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0014-2956 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:20304 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3814 |
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| Author |
Hillidge, C.J.; Lees, P. |
| Title |
Cardiac output in the conscious and anaesthetised horse |
Type |
Journal Article |
| Year |
1975 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
| Volume |
7 |
Issue |
1 |
Pages |
16-21 |
| Keywords |
Anesthesia, Inhalation/*veterinary; Animals; Carbon Dioxide/blood; *Cardiac Output/veterinary; *Consciousness; Electrocardiography/veterinary; Ether, Ethyl; Female; Halothane; Heart Rate; Heart Ventricles/physiology; Horses/*physiology; Hydrogen-Ion Concentration; Male; Oxygen/blood; Posture |
| Abstract |
Cardiac output in the horse was measured before and at predetermined times during 2-hour periods of thiopentone-halothane and thiopentone-diethyl ether anaesthesia. Left ventricular stroke volume was decreased to a similar extent during anaesthesia with each volatile agent, but a greater reduction in cardiac output occurred during halothane anaesthesia. This finding reflected the differing effects of halothane and ether on heart rate, a slight bradycardia occurring with the former agent while ether produced a small degree of tachycardia. The latter effect was attributed to enhanced sympathoadrenal activity. Changes in cardiac output and stroke volume were considered in relation to other factors, including arterial blood pH and tensions of oxygen and carbon dioxide. Positive correlations between some of these variables and cardiac function were established. With both volatile agents the reductions in stroke volume and cardiac output were related to the duration of anaesthesia, being greatest during the early stages. Possible reasons for the tendency of stroke volume and cardiac output to return towards control levels are discussed. |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0425-1644 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:234842 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
102 |
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| Author |
Dunn, M.F.; Branlant, G. |
| Title |
Roles of zinc ion and reduced coenzyme in horse liver alcohol dehydrogenase catalysis. The mechanism of aldehyde activation |
Type |
Journal Article |
| Year |
1975 |
Publication |
Biochemistry |
Abbreviated Journal |
Biochemistry |
| Volume |
14 |
Issue |
14 |
Pages |
3176-3182 |
| Keywords |
*Alcohol Oxidoreductases/metabolism; Aldehydes/*pharmacology; Animals; Binding Sites; Enzyme Activation/drug effects; Horses; Hydrogen-Ion Concentration; Kinetics; Liver/enzymology; *NAD/analogs & derivatives/pharmacology; Oxidation-Reduction; Protein Binding; Spectrophotometry; Spectrophotometry, Ultraviolet; Temperature; *Zinc/pharmacology |
| Abstract |
1,4,5,6-Tetrahydronicotinamide adenine dinucleotide (H2NADH) has been investigated as a reduced coenzyme analog in the reaction between trans-4-N,N-dimethylaminocinnamaldehyde (I) (lambdamax 398 nm, epsilonmax 3.15 X 10-4 M-minus 1 cm-minus 1) and the horse liver alcohol dehydrogenase-NADH complex. These equilibrium binding and temperature-jump kinetic studies establish the following. (i) Substitution of H2NADH for NADH limits reaction to the reversible formation of a new chromophoric species, lambdamax 468 nm, epsilonmax 5.8 x 10-4 M-minus 1 cm-minus 1. This chromophore is demonstrated to be structurally analogous to the transient intermediate formed during the reaction of I with the enzyme-NADH complex [Dunn, M. F., and Hutchison, J. S. (1973), Biochemistry 12, 4882]. (ii) The process of intermediate formation with the enzyme-NADH complex is independent of pH over the range 6.13-10.54. Although studies were limited to the pH range 5.98-8.72, a similar pH independence appears to hold for the H2NADH system. (iii) Within the ternary complex, I is bound within van der Waal's contact distance of the coenzyme nicotinamide ring. (iv) Formation of the transient intermediate does not involve covalent modification of coenzyme. Based on these findings, we conclude that zinc ion has a Lewis acid function in facilitating the chemical activation of the aldehyde carbonyl for reduction, and that reduced coenzyme plays a noncovalent effector role in this substrate activating step. |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0006-2960 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:238585 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3817 |
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| Author |
Steinhoff, H.J.; Lieutenant, K.; Redhardt, A. |
| Title |
Conformational transition of aquomethemoglobin: intramolecular histidine E7 binding reaction to the heme iron in the temperature range between 220 K and 295 K as seen by EPR and temperature-jump measurements |
Type |
Journal Article |
| Year |
1989 |
Publication |
Biochimica et Biophysica Acta |
Abbreviated Journal |
Biochim Biophys Acta |
| Volume |
996 |
Issue |
1-2 |
Pages |
49-56 |
| Keywords |
Animals; Electron Spin Resonance Spectroscopy; Heme; Histidine; Horses; Humans; Hydrogen-Ion Concentration; Methemoglobin/*ultrastructure; Motion; Protein Conformation; Temperature; Thermodynamics; Water |
| Abstract |
Temperature-dependent EPR and temperature-jump measurements have been carried out, in order to examine the high-spin to low-spin transition of aquomethemogobin (pH 6.0). Relaxation rates and equilibrium constants could be determined as a function of temperature. As a reaction mechanism for the high-spin to low-spin transition, the binding of N epsilon of His E7 to the heme iron had been proposed; the same mechanism had been suggested for the ms-effect, found in temperature-jump experiments on aquomethemoglobin. A comparison of the thermodynamic quantities, deduced form the measurements in this paper, gives evidence that indeed the same reaction is investigated in both cases. Our results and most of the findings of earlier studies on the spin-state transitions of aquomethemoglobin, using susceptibility, optical, or EPR measurements, can be explained by the transition of methemoglobin with H2O as ligand (with high-spin state at all temperatures) and methemoglobin with ligand N epsilon of His E7 (with a low-spin ground state). Thermal fluctuations of large amplitude have to be postulated for the reaction to take place, so this reaction may be understood as a probe for the study of protein dynamics. |
| Address |
Institut fur Biophysik, Ruhr-Universitat Bochum, F.R.G |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0006-3002 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:2544230 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3803 |
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| Author |
Hughes, K.L.; Sulaiman, I. |
| Title |
The ecology of Rhodococcus equi and physicochemical influences on growth |
Type |
Journal Article |
| Year |
1987 |
Publication |
Veterinary Microbiology |
Abbreviated Journal |
Vet Microbiol |
| Volume |
14 |
Issue |
3 |
Pages |
241-250 |
| Keywords |
Animals; Feces/microbiology; Horses; Hydrogen-Ion Concentration; Rhodococcus/*growth & development; *Soil Microbiology; Temperature |
| Abstract |
Growth of Rhodococcus equi was studied in vitro. Optimal growth occurred under aerobic conditions between pH 7.0 and 8.5, at 30 degrees C. R. equi survived better in a neutral soil (pH 7.3) than it did in two acid soils (pH less than 5.5). It grew substantially better in soils enriched with faeces than in soils alone. Simple organic acids in horse dung, especially acetate and propionate, appear to be important in supporting growth of R. equi in the environment. The ecology of R. equi can be best explained by an environmental cycle allowing its proliferation in dung, influenced by management, grazing behaviour and prevailing climatic conditions. Preventive measures should be aimed at reducing or avoiding focal areas of faecal contamination in the environment. |
| Address |
School of Veterinary Science, University of Melbourne, Parkville, Vic., Australia |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0378-1135 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:3672866 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2678 |
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| Author |
Rodier, F. |
| Title |
[Spectral properties of porcine plasminogen: study of the acidic transition (author's transl)] |
Type |
Journal Article |
| Year |
1976 |
Publication |
European journal of biochemistry / FEBS |
Abbreviated Journal |
Eur J Biochem |
| Volume |
63 |
Issue |
2 |
Pages |
553-562 |
| Keywords |
Animals; Binding Sites; Guanidines; Hydrogen-Ion Concentration; *Plasminogen; Protein Binding; Protein Conformation; Spectrometry, Fluorescence; Spectrophotometry; Spectrophotometry, Ultraviolet; Swine; Temperature |
| Abstract |
The acidic transition of porcine plasminogen, prepared by affinity chromatography, was studied by non-destructive methods. These methods are based on the analysis of the behaviour of the tryptophyls under various conditions. The perturbation of the absorption and emission spectra by pH or temperature and the dynamic quenching of the intrinsic fluorescence are used to obtain information on structural changes which affect the environment of these residues. It is shown that by decreasing pH the fluorescence emission spectra are shifted toward the long wavelengths, with a broadening of the fluorescence band. The same effect can be obtained at constant pH by heating the protein solution. In order to analyze these phenomena, it is assumed that the fluorescence intensities at 355 nm and 328 nm reflect the proportion of the tryptophans which are exposed to the solvent, and buried, respectively. The plot of the ratio of the fluorescence intensities at these wavelengths versus pH or temperature leads to a titration curve showing an unmasking of tryptophans. The proportion of exposed tryptophans is measured by the dynamic fluorescence quenching technique and the data analyzed according to Lehrer. The plot of the fraction of exposed tryptophyls versus pH also shows the unmasking of these chromophores. Thermal perturbation of a solution of plaminogen at neutral pH induces a difference absorption spectrum whose amplitudes at the maxima are proportional to the number of exposed aromatic residues. The comparison with a solution of fully denatured plasminogen in 6 M guanidium chloride, where all the tryptophyls are exposed, shows that the percentage of exposure is equal to 59%. This number is significantly higher than the percentage found by the fluorescence quenching technique (20%), indicating that some tryptophyls are located in crevices, exposed to the solvent but not to the iodide. At acidic pH the absorption difference spectra induced by thermal perturbation are not classical, since they show an inversion and a new band between 300 nm and 305 nm. This band is mentioned in the literature as a minor band of tryptophan which appears when this chromophore is located in an asymmetric environment. On plotting the maximum amplitude of these spectra obtained at acidic pH versus temperature, we obtain a curve indicating that two types of antagonistic interactions are involved in the perturbation of the chromophores spectra. The spectrophotometric titration of plasminogen gives classical absorption difference spectra. By plotting the maximum amplitude at 292 nm versus pH, we obtain a titration curve with an apparent pK of 2.9 units. This pK is acidic which respect to the pK value of a normal carboxyl. This low value can be due to a positively charged group in the neighbourhood of a carboxyl, which interacts with one or more chromophores. When the carboxyl becomes protonated, this positively charged group is free and available to perturb the environment of some chromophores... |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
French |
Summary Language |
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Original Title |
Proprietes spectrales du plasminogene porcin. Etude de la transition acide |
| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0014-2956 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:4326 |
Approved |
no |
| Call Number |
Admin @ knut @ |
Serial |
22 |
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| Author |
Czerlinski, G.H.; Erickson, J.O.; Theorell, H. |
| Title |
Chemical relaxation studies on the horse liver alcohol dehydrogenase system |
Type |
Journal Article |
| Year |
1979 |
Publication |
Physiological Chemistry and Physics |
Abbreviated Journal |
Physiol Chem Phys |
| Volume |
11 |
Issue |
6 |
Pages |
537-569 |
| Keywords |
Alcohol Oxidoreductases/*metabolism; Animals; Buffers; Electron Transport; Ethanol/metabolism; Horses; Hydrogen-Ion Concentration; Liver/*enzymology; Mathematics; NAD/metabolism; Oscillometry; Osmolar Concentration; Temperature; Time Factors |
| Abstract |
Chemical relaxation studies on the system horse liver alcohol dehydrogenase, nicotinamide adenine dinucleotide, and ethanol were conducted observing fluorescence changes between 400 and 500 nm. Temperature-jump experiments were performed at pH 6.5, 7.0, 8.0, and 9.0; concentration-jump experiments at pH 9.0. The reciprocal of the slowest relaxation time was found to be linearly dependent upon the enzyme concentration for relatively low enzyme concentrations, as predicted earlier. Use of the wide pH-range necessitated expression of the four apparent dissociation constants of the catalytic reaction cycle in terms of pH-independent constants. The system was described in terms of only one (or two) catalysis-linked protons not associated with the electron transfer. Protonic steps in a buffered system are in rapid equilibrium, too fast to be measured with the equipment available. Assuming only two of the four bimolecular reaction steps in the four-step cycle are fast compared to the remaining two, six cases may be considered with six expressions for the reciprocal of the slowest relaxation time. Comparison with the experimental data revealed that the bimolecular reaction steps governing the slowest relaxation time change with pH. Above the effective time resolution of the temperature-lump instrument with fluorescence detection (0.1 msec) only one other relaxation time was detectable and only at pH 9. This relaxation time, found to be independent of the concentration of all reactants within experimental error (r = 10 +/- 5 msec), is most likely due to an interconversion among ternary complexes. |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0031-9325 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:44918 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3813 |
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