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	Author	Saigo, S.
	Title	Kinetic and equilibrium studies of alkaline isomerization of vertebrate cytochromes c			Type	Journal Article
	Year	1981	Publication	Biochimica et Biophysica Acta	Abbreviated Journal	Biochim Biophys Acta
	Volume	669	Issue	1	Pages	13-20
	Keywords	Amino Acid Sequence; Animals; Cytochrome c Group/*metabolism; Dogs; Hydrogen-Ion Concentration; Isomerism; Kinetics; Vertebrates/metabolism
	Abstract	Equilibria and kinetics of alkaline isomerization of seven ferricytochromes c from vertebrates were studied by pH-titration and pH-jump methods in the pH region of 7-12. In the equilibrium behavior, no significant difference was detected among the cytochromes c, whereas marked differences in the kinetic behavior were observed. According to the kinetic behavior of the isomerization, the cytochromes c examined fall into three classes: Group I (horse, sheep, dog and pigeon cytochromes c), Group II (tuna and bonito cytochromes c) and Group III (rhesus monkey cytochrome c). The kinetic results are interpreted in terms of the sequential scheme: Neutral form in equilibrium with fast Transient form in equilibrium with slow Alkaline form where the neutral and alkaline forms are the species stable at neutral and alkaline pH, respectively, and the transient form is a kinetic intermediate. From comparison of the primary sequences of the seven cytochromes c and the classification of these cytochromes c, it is concluded that the amino acid substitution Phe/Tyr at the 46-th position has a major influence on the kinetic behavior. In Group II and III cytochromes c, the ionization of Tyr-46 is suggested to bring about loosening of the heme crevice and thus facilitate the ligand replacement involved in the isomerization.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0006-3002	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:6271238			Approved	no
	Call Number	refbase @ user @			Serial	3871
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	Author	Dyson, H.J.; Beattie, J.K.
	Title	Spin state and unfolding equilibria of ferricytochrome c in acidic solutions			Type	Journal Article
	Year	1982	Publication	The Journal of Biological Chemistry	Abbreviated Journal	J Biol Chem
	Volume	257	Issue	5	Pages	2267-2273
	Keywords	Animals; *Cytochrome c Group; Electron Spin Resonance Spectroscopy; Heme; Horses; Hydrogen-Ion Concentration; Kinetics; Ligands; Myocardium; Protein Binding; Protein Conformation; Spectrophotometry; Temperature
	Abstract	Equilibrium, stopped flow, and temperature-jump spectrophotometry have been used to identify processes in the unfolding of ferricytochrome c in acidic aqueous solutions. A relaxation occurring in approximately 100 microseconds involves perturbation of a spin-equilibrium between two folded conformers of the protein with methionine-80 coordinated or dissociated from the heme iron. The protein unfolds more slowly, in milliseconds, with dissociation and protonation of histidine-18. These two transitions appear cooperative in equilibrium measurements at low (0.01 M) ionic strength, but are separated at higher (0.10 M) ionic strength. They are resolved under both conditions in the dynamic measurements. The spin-equilibrium description permits a unified explanation of a number of properties of ferricytochrome c in acidic aqueous solutions.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0021-9258	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:6277891			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3807
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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
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0378-1135	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:3672866			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	2678
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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
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0006-3002	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:2544230			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3803
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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				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0425-1644	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:1915234			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3801
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	Author	Hinchcliff, K.W.; Kohn, C.W.; Geor, R.; McCutcheon, L.J.; Foreman, J.; Andrews, F.M.; Allen, A.K.; White, S.L.; Williamson, L.H.; Maykuth, P.L.
	Title	Acid:base and serum biochemistry changes in horses competing at a modified 1 Star 3-day-event			Type	Journal Article
	Year	1995	Publication	Equine Veterinary Journal. Supplement	Abbreviated Journal	Equine Vet J Suppl
	Volume		Issue	20	Pages	105-110
	Keywords	Acid-Base Equilibrium; Animals; Blood Proteins/analysis; Body Water/metabolism; Carbon Dioxide/blood; Electrolytes/blood; Female; Hematocrit/veterinary; Homeostasis; Horses/blood/physiology; Hydrogen-Ion Concentration; Male; Physical Conditioning, Animal/physiology
	Abstract	We examined the effects of participation in each of 3 modifications of Day 2 of a 3-day-event on blood and serum variables indicative of hydration, acid:base status and electrolyte homeostasis of horses. Three groups of horses – 8 European (E) horses and 2 groups each of 9 North American horses performed identical Days 1 (dressage) and 3 (stadium jumping) of a 3-day-event. E horses and one group of the North American horses (TD) performed modifications of Day 2 of a 1 Star 3-day-event and the other group of North American horses (HT) performed a Horse Trial on Day 2. Jugular venous blood was collected from each horse on the morning of Day 2 before any warm-up activity, between 4 min 55 s and 5 min 15 s after Phase D and the following morning. Eight E horses, 5 TD horses and 8 HT horses completed the trials. There were few significant differences in acid:base or serum biochemistry variables detected among horses performing either 2 variations of the Speed and Endurance day of a 1 Star 3-day-event, or a conventional Horse Trial. Failure to detect differences among groups may have been related to the low statistical power associated with the small number of horses, especially in the TD group, variation in quality of horses among groups and the different times of the day at which the E horses competed. Differences detected among time points were usually common to all groups and demonstrated metabolic acidosis with a compensatory respiratory alkalosis, a reduction in total body water and cation content, and hypocalcaemia. Importantly, horses of all groups did not replenish cation, chloride, and calcium deficits after 14-18 h of recovery.
	Address	Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, Columbus 43210-1089, USA
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:8933092			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3740
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	Author	Abbruzzetti, S.; Crema, E.; Masino, L.; Vecli, A.; Viappiani, C.; Small, J.R.; Libertini, L.J.; Small, E.W.
	Title	Fast events in protein folding: structural volume changes accompanying the early events in the N-->I transition of apomyoglobin induced by ultrafast pH jump			Type	Journal Article
	Year	2000	Publication	Biophysical Journal	Abbreviated Journal	Biophys J
	Volume	78	Issue	1	Pages	405-415
	Keywords	Animals; Apoproteins/chemistry; Horses; Hydrogen-Ion Concentration; Kinetics; Models, Molecular; Myoglobin/chemistry; Protein Conformation; Protein Folding; Protein Structure, Secondary; Spectrometry, Fluorescence
	Abstract	Ultrafast, laser-induced pH jump with time-resolved photoacoustic detection has been used to investigate the early protonation steps leading to the formation of the compact acid intermediate (I) of apomyoglobin (ApoMb). When ApoMb is in its native state (N) at pH 7.0, rapid acidification induced by a laser pulse leads to two parallel protonation processes. One reaction can be attributed to the binding of protons to the imidazole rings of His24 and His119. Reaction with imidazole leads to an unusually large contraction of -82 +/- 3 ml/mol, an enthalpy change of 8 +/- 1 kcal/mol, and an apparent bimolecular rate constant of (0.77 +/- 0.03) x 10(10) M(-1) s(-1). Our experiments evidence a rate-limiting step for this process at high ApoMb concentrations, characterized by a value of (0. 60 +/- 0.07) x 10(6) s(-1). The second protonation reaction at pH 7. 0 can be attributed to neutralization of carboxylate groups and is accompanied by an apparent expansion of 3.4 +/- 0.2 ml/mol, occurring with an apparent bimolecular rate constant of (1.25 +/- 0.02) x 10(11) M(-1) s(-1), and a reaction enthalpy of about 2 kcal/mol. The activation energy for the processes associated with the protonation of His24 and His119 is 16.2 +/- 0.9 kcal/mol, whereas that for the neutralization of carboxylates is 9.2 +/- 0.9 kcal/mol. At pH 4.5 ApoMb is in a partially unfolded state (I) and rapid acidification experiments evidence only the process assigned to carboxylate protonation. The unusually large contraction and the high energetic barrier observed at pH 7.0 for the protonation of the His residues suggests that the formation of the compact acid intermediate involves a rate-limiting step after protonation.
	Address	Dipartimento di Fisica, Universita di Parma, 43100 Parma, Italia
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0006-3495	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:10620304			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3792
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	Author	Pierce, M.M.; Nall, B.T.
	Title	Coupled kinetic traps in cytochrome c folding: His-heme misligation and proline isomerization			Type	Journal Article
	Year	2000	Publication	Journal of Molecular Biology	Abbreviated Journal	J Mol Biol
	Volume	298	Issue	5	Pages	955-969
	Keywords	Amino Acid Sequence; Amino Acid Substitution/genetics; Binding Sites; Cytochrome c Group/chemistry/genetics/metabolism; Cytochromes c; Enzyme Stability/drug effects; Fluorescence; Guanidine/pharmacology; Heme/metabolism; Histidine/genetics/metabolism; Hydrogen-Ion Concentration; Isomerism; Kinetics; Models, Molecular; Molecular Sequence Data; Mutation/genetics; Proline/chemistry/metabolism; Protein Conformation/drug effects; Protein Denaturation/drug effects; *Protein Folding; Protein Renaturation; Saccharomyces cerevisiae/enzymology/genetics; Sequence Alignment; Thermodynamics
	Abstract	The effect of His-heme misligation on folding has been investigated for a triple mutant of yeast iso-2 cytochrome c (N26H,H33N,H39K iso-2). The variant contains a single misligating His residue at position 26, a location at which His residues are found in several cytochrome c homologues, including horse, tuna, and yeast iso-1. The amplitude for fast phase folding exhibits a strong initial pH dependence. For GdnHCl unfolded protein at an initial pH<5, the observed refolding at final pH 6 is dominated by a fast phase (tau(2f)=20 ms, alpha(2f)=90 %) that represents folding in the absence of misligation. For unfolded protein at initial pH 6, folding at final pH 6 occurs in a fast phase of reduced amplitude (alpha(2f) approximately 20 %) but the same rate (tau(2f)=20 ms), and in two slower phases (tau(m)=6-8 seconds, alpha(m) approximately 45 %; and tau(1b)=16-20 seconds, alpha(1b) approximately 35 %). Double jump experiments show that the initial pH dependence of the folding amplitudes results from a slow pH-dependent equilibrium between fast and slow folding species present in the unfolded protein. The slow equilibrium arises from coupling of the His protonation equilibrium to His-heme misligation and proline isomerization. Specifically, Pro25 is predominantly in trans in the unligated low-pH unfolded protein, but is constrained in a non-native cis isomerization state by His26-heme misligation near neutral pH. Refolding from the misligated unfolded form proceeds slowly due to the large energetic barrier required for proline isomerization and displacement of the misligated His26-heme ligand.
	Address	Center for Biomolecular Structure, Department of Biochemistry, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0022-2836	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:10801361			Approved	no
	Call Number	refbase @ user @			Serial	3853
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	Author	Abbruzzetti, S.; Viappiani, C.; Small, J.R.; Libertini, L.J.; Small, E.W.
	Title	Kinetics of histidine deligation from the heme in GuHCl-unfolded Fe(III) cytochrome C studied by a laser-induced pH-jump technique			Type	Journal Article
	Year	2001	Publication	Journal of the American Chemical Society	Abbreviated Journal	J Am Chem Soc
	Volume	123	Issue	27	Pages	6649-6653
	Keywords	Animals; Bacterial Proteins; Cytochrome c Group/chemistry; Guanidine/chemistry; Heme/chemistry; Histidine/chemistry; Horses; Hydrogen-Ion Concentration; Kinetics; Lasers; Ligands; Protein Folding
	Abstract	We have developed an instrumental setup that uses transient absorption to monitor protein folding/unfolding processes following a laser-induced, ultrafast release of protons from o-nitrobenzaldehyde. The resulting increase in [H(+)], which can be more than 100 microM, is complete within a few nanoseconds. The increase in [H(+)] lowers the pH of the solution from neutrality to approximately 4 at the highest laser pulse energy used. Protein structural rearrangements can be followed by transient absorption, with kinetic monitoring over a broad time range (approximately 10 ns to 500 ms). Using this pH-jump/transient absorption technique, we have examined the dissociation kinetics of non-native axial heme ligands (either histidine His26 or His33) in GuHCl-unfolded Fe(III) cytochrome c (cyt c). Deligation of the non-native ligands following the acidic pH-jump occurs as a biexponential process with different pre-exponential factors. The pre-exponential factors markedly depend on the extent of the pH-jump, as expected from differences in the pK(a) values of His26 and His33. The two lifetimes were found to depend on temperature but were not functions of either the magnitude of the pH-jump or the pre-pulse pH of the solution. The activation energies of the deligation processes support the suggestion that GuHCl-unfolded cyt c structures with non-native histidine axial ligands represent kinetic traps in unfolding.
	Address	Dipartimento di Fisica, Universita di Parma, Istituto Nazionale per la Fisica della Materia, 43100 Parma, Italy
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0002-7863	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11439052			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3788
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	Author	Gulotta, M.; Gilmanshin, R.; Buscher, T.C.; Callender, R.H.; Dyer, R.B.
	Title	Core formation in apomyoglobin: probing the upper reaches of the folding energy landscape			Type	Journal Article
	Year	2001	Publication	Biochemistry	Abbreviated Journal	Biochemistry
	Volume	40	Issue	17	Pages	5137-5143
	Keywords	Animals; Apoproteins/chemistry; Computer Simulation; Horses; Hydrogen-Ion Concentration; Kinetics; Models, Molecular; Myoglobin/chemistry; *Protein Folding; Protein Structure, Secondary; Protein Structure, Tertiary; Spectrometry, Fluorescence/instrumentation/methods; Thermodynamics; Tryptophan/chemistry
	Abstract	An acid-destabilized form of apomyoglobin, the so-called E state, consists of a set of heterogeneous structures that are all characterized by a stable hydrophobic core composed of 30-40 residues at the intersection of the A, G, and H helices of the protein, with little other secondary structure and no other tertiary structure. Relaxation kinetics studies were carried out to characterize the dynamics of core melting and formation in this protein. The unfolding and/or refolding response is induced by a laser-induced temperature jump between the folded and unfolded forms of E, and structural changes are monitored using the infrared amide I' absorbance at 1648-1651 cm(-1) that reports on the formation of solvent-protected, native-like helix in the core and by fluorescence emission changes from apomyoglobin's Trp14, a measure of burial of the indole group of this residue. The fluorescence kinetics data are monoexponential with a relaxation time of 14 micros. However, infrared kinetics data are best fit to a biexponential function with relaxation times of 14 and 59 micros. These relaxation times are very fast, close to the limits placed on folding reactions by diffusion. The 14 micros relaxation time is weakly temperature dependent and thus represents a pathway that is energetically downhill. The appearance of this relaxation time in both the fluorescence and infrared measurements indicates that this folding event proceeds by a concomitant formation of compact secondary and tertiary structures. The 59 micros relaxation time is much more strongly temperature dependent and has no fluorescence counterpart, indicating an activated process with a large energy barrier wherein nonspecific hydrophobic interactions between helix A and the G and H helices cause some helix burial but Trp14 remains solvent exposed. These results are best fit by a multiple-pathway kinetic model when U collapses to form the various folded core structures of E. Thus, the results suggest very robust dynamics for core formation involving multiple folding pathways and provide significant insight into the primary processes of protein folding.
	Address	Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0006-2960	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11318635			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3789
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