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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	Haruta, N.; Kitagawa, T.
	Title	Time-resolved UV resonance Raman investigation of protein folding using a rapid mixer: characterization of kinetic folding intermediates of apomyoglobin			Type	Journal Article
	Year	2002	Publication	Biochemistry	Abbreviated Journal	Biochemistry
	Volume	41	Issue	21	Pages	6595-6604
	Keywords	Animals; Apoproteins/chemistry; Circular Dichroism; Holoenzymes/chemistry; Horses; Hydrochloric Acid/chemistry; Hydrogen-Ion Concentration; Imidazoles/chemistry; Kinetics; Models, Molecular; Myoglobin/chemistry; Peptide Fragments/chemistry; Protein Folding; Protein Structure, Secondary; Spectrum Analysis, Raman/methods; Tryptophan/*chemistry; Ultraviolet Rays; Whales
	Abstract	The 244-nm excited transient UV resonance Raman spectra are observed for the refolding intermediates of horse apomyoglobin (h-apoMb) with a newly constructed mixed flow cell system, and the results are interpreted on the basis of the spectra observed for the equilibrium acid unfolding of the same protein. The dead time of mixing, which was determined with the appearance of UV Raman bands of imidazolium upon mixing of imidazole with acid, was 150 micros under the flow rate that was adopted. The pH-jump experiments of h-apoMb from pH 2.2 to 5.6 conducted with this device demonstrated the presence of three folding intermediates. On the basis of the analysis of W3 and W7 bands of Trp7 and Trp14, the first intermediate, formed before 250 micros, involved incorporation of Trp14 into the alpha-helix from a random coil. The frequency shift of the W3 band of Trp14 observed for this process was reproduced with a model peptide of the A helix when it forms the alpha-helix. In the second intermediate, formed around 1 ms after the start of refolding, the surroundings of both Trp7 and Trp14 were significantly hydrophobic, suggesting the formation of the hydrophobic core. In the third intermediate appearing around 3 ms, the hydrophobicity was relaxed to the same level as that of the pH 4 equilibrium intermediate, which was investigated in detail with the stationary state technique. The change from the third intermediate to the native state needs more time than 40 ms, while the appearance of the native spectrum after the mixing of the same solutions was confirmed separately.
	Address	School of Mathematical and Physical Sciences, The Graduate University for Advanced Studies, Myodaiji, Okazaki 444-8585, Japan
	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:12022863			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3785
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	Author	Ballew, R.M.; Sabelko, J.; Gruebele, M.
	Title	Direct observation of fast protein folding: the initial collapse of apomyoglobin			Type	Journal Article
	Year	1996	Publication	Proceedings of the National Academy of Sciences of the United States of America	Abbreviated Journal	Proc. Natl. Acad. Sci. U.S.A.
	Volume	93	Issue	12	Pages	5759-5764
	Keywords	Animals; Apoproteins/chemistry; Circular Dichroism; Horses; Kinetics; Muscle, Skeletal/chemistry; Myoglobin/chemistry; *Protein Folding; Spectrometry, Fluorescence; Spectrophotometry, Infrared; Temperature
	Abstract	The rapid refolding dynamics of apomyoglobin are followed by a new temperature-jump fluorescence technique on a 15-ns to 0.5-ms time scale in vitro. The apparatus measures the protein-folding history in a single sweep in standard aqueous buffers. The earliest steps during folding to a compact state are observed and are complete in under 20 micros. Experiments on mutants and consideration of steady-state CD and fluorescence spectra indicate that the observed microsecond phase monitors assembly of an A x (H x G) helix subunit. Measurements at different viscosities indicate diffusive behavior even at low viscosities, in agreement with motions of a solvent-exposed protein during the initial collapse.
	Address	School of Chemical Sciences and Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, 61801, 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	0027-8424	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:8650166			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3798
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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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	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.
	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	0006-2960	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:238585			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3817
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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	Saigo, S.
	Title	A transient spin-state change during alkaline isomerization of ferricytochrome c			Type	Journal Article
	Year	1981	Publication	Journal of Biochemistry	Abbreviated Journal	J Biochem (Tokyo)
	Volume	89	Issue	6	Pages	1977-1980
	Keywords	Animals; *Cytochrome c Group; Horses; Hydrogen-Ion Concentration; Isomerism; Kinetics; Myocardium/enzymology; Oxidation-Reduction; Spectrophotometry
	Abstract	Kinetic difference spectra during the alkaline isomerization of ferricytochrome c were obtained by the pH-jump method in the range of 540 to 655 nm. The spectrum of the transient intermediate, which appears during the course of the isomerization, was reproduced from the spectra. The intermediate showed an intense absorption band at 600 nm, indicating that it is a high spin or mixed spin species. This is in contrast to the stable neutral and alkaline forms which are low spin species. The transient spin-state change during the isomerization was also observed upon rapid oxidation of ferrocytochrome c at alkaline pH.
	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	0021-924X	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:6270075			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3808
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	Author	Ridge, J.A.; Baldwin, R.L.; Labhardt, A.M.
	Title	Nature of the fast and slow refolding reactions of iron(III) cytochrome c			Type	Journal Article
	Year	1981	Publication	Biochemistry	Abbreviated Journal	Biochemistry
	Volume	20	Issue	6	Pages	1622-1630
	Keywords	Animals; Ascorbic Acid; *Cytochrome c Group; Guanidines; Horses; Kinetics; Oxidation-Reduction; Protein Conformation; Spectrum Analysis
	Abstract	The fast and slow refolding reactions of iron(III) cytochrome c (Fe(III) cyt c), previously studied by Ikai et al. (Ikai, A., Fish, W. W., & Tanford, C. (1973) J. Mol. Biol. 73, 165--184), have been reinvestigated. The fast reaction has the major amplitude (78%) and is 100-fold faster than the slow reaction in these conditions (pH 7.2, 25 degrees C, 1.75 M guanidine hydrochloride). We show here that native cyt c is the product formed in the fast reaction as well as in the slow reaction. Two probes have been used to test for formation of native cyt c. absorbance in the 695-nm band and rate of reduction of by L-ascorbate. Different unfolded species (UF, US) give rise to the fast and slow refolding reactions, as shown both by refolding assays at different times after unfolding (“double-jump” experiments) and by the formation of native cyt c in each of the fast and slow refolding reactions. Thus the fast refolding reaction is UF leads to N and the slow refolding reaction is Us leads to N, where N is native cyt c, and there is a US in equilibrium UF equilibrium in unfolded cyt c. The results are consistent with the UF in equilibrium US reaction being proline isomerization, but this has not yet been tested in detail. Folding intermediates have been detected in both reactions. In the UF leads to N reaction, the Soret absorbance change precedes the recovery of the native 695-nm band spectrum, showing that Soret absorbance monitors the formation of a folding intermediate. In the US leads to N reaction an ascorbate-reducible intermediate has been found at an early stage in folding and the Soret absorbance change occurs together with the change at 695 nm as N is formed in the final stage of folding.
	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	0006-2960	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:6261802			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3809
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	Author	Bykov, S.; Lednev, I.; Ianoul, A.; Mikhonin, A.; Munro, C.; Asher, S.A.
	Title	Steady-state and transient ultraviolet resonance Raman spectrometer for the 193-270 nm spectral region			Type	Journal Article
	Year	2005	Publication	Applied Spectroscopy	Abbreviated Journal	Appl Spectrosc
	Volume	59	Issue	12	Pages	1541-1552
	Keywords	Animals; Equipment Design; Equipment Failure Analysis; Horses; Kinetics; Metmyoglobin/analysis; Myocardium/metabolism; Reproducibility of Results; Sensitivity and Specificity; Spectrophotometry, Ultraviolet/instrumentation/methods; Spectrum Analysis, Raman/instrumentation/methods
	Abstract	We describe a state-of-the-art tunable ultraviolet (UV) Raman spectrometer for the 193-270 nm spectral region. This instrument allows for steady-state and transient UV Raman measurements. We utilize a 5 kHz Ti-sapphire continuously tunable laser (approximately 20 ns pulse width) between 193 nm and 240 nm for steady-state measurements. For transient Raman measurements we utilize one Coherent Infinity YAG laser to generate nanosecond infrared (IR) pump laser pulses to generate a temperature jump (T-jump) and a second Coherent Infinity YAG laser that is frequency tripled and Raman shifted into the deep UV (204 nm) for transient UV Raman excitation. Numerous other UV excitation frequencies can be utilized for selective excitation of chromophoric groups for transient Raman measurements. We constructed a subtractive dispersion double monochromator to minimize stray light. We utilize a new charge-coupled device (CCD) camera that responds efficiently to UV light, as opposed to the previous CCD and photodiode detectors, which required intensifiers for detecting UV light. For the T-jump measurements we use a second camera to simultaneously acquire the Raman spectra of the water stretching bands (2500-4000 cm(-1)) whose band-shape and frequency report the sample temperature.
	Address	Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, 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	0003-7028	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:16390595			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3767
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	Author	Jallon, J.M.; Risler, Y.; Iwatsubo, M.
	Title	Beef liver L-Glutamate dehydrogenase mechanism: presteady state study of the catalytic reduction of 2.oxoglutarate by NADPH			Type	Journal Article
	Year	1975	Publication	Biochemical and biophysical research communications	Abbreviated Journal	Biochem Biophys Res Commun
	Volume	67	Issue	4	Pages	1527-1536
	Keywords	Animals; Cattle; Glutamate Dehydrogenase/metabolism; Ketoglutaric Acids; Kinetics; Liver/enzymology; Nadp; Oxidation-Reduction; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet
	Abstract
	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	0006-291X	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:1038			Approved	no
	Call Number	Admin @ knut @			Serial	21
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