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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 (down) 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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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 Schmoldt, A.; Benthe, H.F.; Haberland, G.
Title Digitoxin metabolism by rat liver microsomes Type Journal Article
Year 1975 Publication Biochemical pharmacology Abbreviated Journal Biochem Pharmacol
Volume 24 Issue 17 Pages (down) 1639-1641
Keywords Animals; Chromatography, Thin Layer; Digitoxigenin/metabolism; Digitoxin/*metabolism; Hydroxylation; Male; Microsomes, Liver/*metabolism; NADP/metabolism; Rats; Time Factors
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Series Volume Series Issue Edition
ISSN 0006-2952 ISBN Medium
Area Expedition Conference
Notes PMID:10 Approved no
Call Number Admin @ knut @ Serial 20
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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 (down) 1527-1536
Keywords Animals; Cattle; Glutamate Dehydrogenase/*metabolism; Ketoglutaric Acids; Kinetics; Liver/*enzymology; Nadp; Oxidation-Reduction; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet
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ISSN 0006-291X ISBN Medium
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Notes PMID:1038 Approved no
Call Number Admin @ knut @ Serial 21
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Author Sivak, J.G.; Allen, D.B.
Title An evaluation of the “ramp” retina of the horse eye Type Journal Article
Year 1975 Publication Vision Research Abbreviated Journal Vision Res
Volume 15 Issue 12 Pages (down) 1353-1356
Keywords Accommodation, Ocular; Animals; Aqueous Humor/physiology; Cornea/physiology; Freezing; Horses/*anatomy & histology; Lens, Crystalline/anatomy & histology/physiology; Refraction, Ocular; Retina/*anatomy & histology; Vitreous Body/physiology
Abstract Using a rapid freezing and sectioning technique, the distance between the lens and retina of the horse eye was measured. There is no indication of a ramp retina that could serve accommodation. The pupil axis of the eye coincides with the maximum lens to retina distance. The changes in the lens-retina distance are greater below the axis than above it. Calculations were made of refractive power of the horse eye from measurements of curvature and refractive indices of the ocular tissues. These calculations agree both qualitatively and quantitatively with retinoscopic measurements on live horses. Both show that the refractive state shifts in the direction of hyperopia above and below the axis and that this shift is greater below the axis than above it. Some dynamic accommodative ability in the living eye was observed.
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ISSN 0042-6989 ISBN Medium
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Notes PMID:1210017 Approved no
Call Number Equine Behaviour @ team @ Serial 3647
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Author Syme, G.J.; Syme, L.A.
Title The concept of spatial leadership in farm animals: An experiment with sheep Type Journal Article
Year 1975 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 23 Issue Part 4 Pages (down) 921-925
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Abstract The concept of spatial leadership as applied to farm animals is discussed with particular emphasis on methodological problems. Using three experimental procedures forced spatial leadership orders were measured in a group of Romney ewes. Comparisons between orders showed the effects of both the different experimental tasks and the social context on leadership structure. Both these variables were found to affect the orders obtained. The results are interpreted in terms of the utility of the concept of spatial leadership in domestic animals and the necessity for more systematic procedural investigations in this area.
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Notes Approved no
Call Number Serial 2039
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Author Czerlinski, G.H.; Wagner, M.; Erickson, J.O.; Theorell, H.
Title Chemical relaxation studies on the system liver alcohol dehydrogenase, NADH and imidazole Type Journal Article
Year 1975 Publication Acta Chemica Scandinavica. Series B: Organic Chemistry and Biochemistry Abbreviated Journal Acta Chem Scand B
Volume 29 Issue 8 Pages (down) 797-810
Keywords Alcohol Oxidoreductases/*metabolism; Animals; Computers; Hydrogen-Ion Concentration; Imidazoles/*metabolism; Kinetics; Liver/enzymology/*metabolism; Mathematics; Models, Chemical; NAD/*metabolism; Time Factors
Abstract Several years ago, Theorell and Czerlinski conducted experiments on the system of horse liver alcohol dehydrogenase, reduced nicotinamide adenine dinucleotide and imidazole, using the first version of the temperature jump apparatus with detection of changes in fluorescence. These early experiments were repeated with improved instrumentation and confirmed the early experiments in general terms. However, the improved detection system allowed to measure a slight concentration dependence of the relaxation time of around 3 ms. Furthermore, the chemical relaxation time was smaller than the one determined earlier (by factor 2). The data were evaluated much more rigorously than before, allowing an appropriate interpretation of the results. The observed relaxation time is largely due to rate constants in an interconversion of ternary complexes, which are faster than three (of the four) dissociation rate constants, determined previously by Theorell and McKinley-McKee.1,2 This fact contributed to earlier difficulties of finding any concentration dependence. However, the binding of imidazole to the binary enzyme-coenzyme complex can be made to couple kinetically into the interconversion rate of the two ternary complexes. The observed signal derives largely from the ternary complex(es). A substantial fluorescence signal change is associated with the observed relaxation process, suggesting a relocation of the imidazole in reference to the nicotinamide moiety of the bound coenzyme. Nine models are considered with two types of coupling of pre-equilibria (none-all). Quantitative evaluations favor the model with two ternary complexes connected by an interconversion outside the four-step (bimolecular) cycle. The ternary complex outside the cycle has much higher fluorescence yield than the one inside. The interconversion equilibrium is near unity for imidazole. If it would be shifted very much to the side of the “dead-end” complex (as in isobutyramide?!), stimulating action could not take place.
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ISSN 0302-4369 ISBN Medium
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Notes PMID:882 Approved no
Call Number refbase @ user @ Serial 3887
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Author Mitchell, D.; Allen, W. R.
Title Observations on reproductive performance in the yearling mare Type Journal Article
Year 1975 Publication Journal of Reproduction and Fertility Abbreviated Journal J. Reprod. Fert.,
Volume (Suppl. 23) Issue Pages (down) 531-536
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Abstract Reproductive performance was studied in 137 yearling mares run with stallions in small groups for 3 months between June and August in 1968 to 1971 (four breeding seasons). Pregnancy diagnosis by repeated rectal palpation and qualitative tests for PMSG, showed that ninety-five mares conceived of which forty-four aborted spontaneously between days 30 and 160 of gestation. Laboratory examination of twenty-one aborted fetuses failed to show any infectious agents. Serial quantitative and qualitative tests for PMSG in aborting animals gave results similar to those observed in mares with normal pregnancies. Plasma progestagen assays showed marked individual variations although the loss of the conceptus was always associated with a drop in progestagen level. The high incidence of early pregnancy loss in these pubertal mares may also be related to immaturity, inadequate nutrition and physical stress.
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 2378
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Author Douglas Rh, G.O.
Title Development of the equine fetus and placenta Type Journal Article
Year 1975 Publication Abbreviated Journal J Reprod Fert (Suppl)
Volume 23 Issue Pages (down) 495-498
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Notes from Professor Hans Klingels Equine Reference List Approved no
Call Number Serial 1023
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Author Niekerk Van Ch, A.W.
Title Early embryonic development in the horse Type Journal Article
Year 1975 Publication Abbreviated Journal J Reprod Fert Suppl
Volume 23 Issue Pages (down) 495-498
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Notes from Professor Hans Klingels Equine Reference List Approved no
Call Number Serial 1417
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Author Montagu I,
Title The wild ass of Africa Type Journal Article
Year 1975 Publication Abbreviated Journal Wild Life
Volume 17 Issue Pages (down) 400-401
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Notes from Professor Hans Klingels Equine Reference List Approved no
Call Number Serial 1409
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