toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author (up) Cho, K.C.; Chan, K.K. url  openurl
  Title Kinetics of cold-induced denaturation of metmyoglobin Type Journal Article
  Year 1984 Publication Biochimica et Biophysica Acta (BBA) – Protein Structure and Molecular Enzymology Abbreviated Journal  
  Volume 786 Issue 1-2 Pages 103-108  
  Keywords Metmyoglobin denaturation; Temperature jump; Denaturation kinetics; Conformational transformation; (Horse heart)  
  Abstract Using a slow temperature-jump spectrophotometer, we have studied the kinetics of cold-induced denaturation of metmyoglobin between 0[degree sign]C and 20[degree sign]C at acidic pH. The time-scale of the transition is slow and is of the order of minutes. The results are consistent with the transition's involving a total of three states, native (N), transient intermediate (I) and denatured (D), which are converted from one to the other in that order.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number refbase @ user @ Serial 3978  
Permanent link to this record
 

 
Author (up) Hasumi, H. openurl 
  Title Kinetic studies on isomerization of ferricytochrome c in alkaline and acid pH ranges by the circular dichroism stopped-flow method Type Journal Article
  Year 1980 Publication Biochimica et Biophysica Acta Abbreviated Journal Biochim Biophys Acta  
  Volume 626 Issue 2 Pages 265-276  
  Keywords Circular Dichroism; *Cytochrome c Group; Hydrogen-Ion Concentration; Isomerism; Kinetics; Spectrophotometry  
  Abstract The isomerization of horse-heart ferricytochrome c caused by varying pH was kinetically studied by using circular dichroism (CD) and optical absorption stopped-flow techniques. In the pH range of 7--13, the existence of the three different forms of ferricytochrome c (pH less than 10, pH 10--12, and pH greater than 12) was indicated from the statistical difference CD spectra. On the basis of analyses of the stopped-flow traces in the near-ultraviolet and Soret wavelength regions, the isomerization of ferricytochrome c from neutral form to the above three alkaline forms was interpreted as follows (1) below pH 10, the replacement of the intrinsic ligand of methionine residue by lysine residue occurs; (2) between pH 10 and 12, the uncoupling of the polypeptide chain from close proximity of the heme group occurs first, followed by the interconversion of the intrinsic ligands; and (3) above pH 12, hydroxide form of ferricytochrome c is formed, though the replacement of the intrinsic ligand by extrinsic ligands may occur via different routes from those below pH 12. The CD changes at 288 nm and in the Soret region caused by the pH-jump (down) from pH 6.0 to 1.6 were compared with the appearance of the 620-nm absorption band ascribed to the formation of the high-spin form of ferricytochrome c. Both CD and absorption changes indicated that the isomerization at pH 1.6 consisted of two processes: one proceeded within the dead-time (about 2 ms) of the stopped-flow apparatus and the other proceeded at a determinable rate with the apparatus. On the basis of these results, the isomerization of ferricytochrome c at pH 1.6 was explained as follows: (1) the transition from the low-spin form to the high-spin forms occurs within about 2 ms, the dead-time of the stopped-flow apparatus; and (2) the polypeptide chain is unfolded after the formation of the high-spin form.  
  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:6260152 Approved no  
  Call Number refbase @ user @ Serial 3876  
Permanent link to this record
 

 
Author (up) Kihara, H. url  openurl
  Title Comparison of the redox reactions of various types of cytochrome c with iron hexacyanides Type Journal Article
  Year 1981 Publication Biochimica et Biophysica Acta (BBA) – Bioenergetics Abbreviated Journal  
  Volume 634 Issue Pages 93-104  
  Keywords Cytochrome c; Redox reaction; Iron hexacyanide; Temperature jump; Electron transfer  
  Abstract The dynamic behavior of various types of cytochromes c in the redox reaction with iron hexacyanides was studied using a temperature-jump method in order to elucidate the molecular mechanism of the redox reaction of cytochromes with their oxidoreductants. Transmittance after the temperature jump changed through a single exponential decay for all cytochromes investigated. Under a constant concentration of anion, the redox reaction of various types of cytochrome c with iron hexacyanides was analyzed according to the scheme: Ki=kt/k-i (i=1,2,3) where C(III) and C(II) are ferric and ferrous cytochromes, respectively, Fe(III) and Fe(II) are ferri- and ferrocyanides, respectively, C(III) [middle dot] Fe(II) is the ferricytochrome-ferrocyanide complex and C(II) [middle dot] Fe(III) is the ferrocytochrome-ferricyanide complex. When step B is slower than the other two steps A and C, τ-1 can be represented approximately as where the bar over the variables denotes the equilibrium value. In a large excess of ferrocyanide against cytochrome, we can estimate k2, k-2, K1 and K3 independently. In the case of horse cytochrome c at 18[degree sign]C in 0.1 M phosphate buffer at pH 7 with 0.3 M KNO3, the estimated parameters are k2 = 100 +/- 50 s-1, k-2 = (3.5 +/- 1.0) [middle dot] 103 s-1, K1 = 15 +/- 7 M-1 and K3 = (8.5 +/- 1.5) [middle dot] 10-4 M. From the same experiments for seven cytochromes (cytochrome c from horse, tuna, Candida krusei, Saccharomyces oviformis, Rhodospirillum rubrum cytochrome c2, Spirulina platensis cytochrome c-554 and Thermus thermophilus cytochrome c-552), the following results can be deduced. (1) Each parameter defined in the scheme above (k2, k-2, K1, K3) diverged beyond the error range. Above all, k2 values of cytochromes c-554 and c-552 are as large as 1 [middle dot] 104 s-1 and much larger than those for the other cytochromes (to 50 approx. 700 S-1). (2) The variance of k2K1 and k-2/K3 are relatively less than the variances of individual parameters (k2, k-2, K1 and K3), which suggests that the values of k2K1 and k-2/K3 have been conserved during the course of evolution.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number refbase @ user @ Serial 3980  
Permanent link to this record
 

 
Author (up) Kihara, H.; Nakatani, H.; Hiromi, K.; Hon-Nami, K. doi  openurl
  Title Kinetic studies on redox reactions of hemoproteins. I. Reduction of thermoresistant cytochrome c-552 and horse heart cytochrome c by ferrocyanide Type Journal Article
  Year 1977 Publication Biochimica et Biophysica Acta Abbreviated Journal Biochim Biophys Acta  
  Volume 460 Issue 3 Pages 480-489  
  Keywords Animals; Bacteria; *Cytochrome c Group; *Ferrocyanides; Horses; Kinetics; Mathematics; Oxidation-Reduction; Spectrophotometry; Spectrophotometry, Ultraviolet; Temperature; Thermodynamics  
  Abstract The oxidation-reduction reaction of horse heart cytochrome c and cytochrome c (552, Thermus thermophilus), which is highly thermoresistant, was studied by temperature-jump method. Ferrohexacyanide was used as reductant. (Formula: see text.) Thermodynamic and activation parameters of the reaction obtained for both cytochromes were compared with each other. The results of this showed that (1) the redox potential of cytochrome c-552, + 0.19 V, is markedly less than that of horse heart cytochrome c. (2) deltaHox of cytochrome c-552 is considerably lower than that of horse heart cytochrome c. (3) deltaSox and deltaSred of cytochrome c-552 are more negative than those of horse heart cytochrome c. (4) kred of cytochrome c-552 is much lower than that of horse heart cytochrome c at room temperature.  
  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:195599 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3815  
Permanent link to this record
 

 
Author (up) Kihara, H.; Nakatani, H.; Hiromi, K.; Hon-Nami, K.; Oshima, T. url  doi
openurl 
  Title Kinetic studies on redox reactions of hemoproteins. I. Reduction of thermoresistant cytochrome c-552 and horse heart cytochrome c by ferrocyanide Type Journal Article
  Year 1977 Publication Biochimica et Biophysica Acta (BBA) – Bioenergetics Abbreviated Journal  
  Volume 460 Issue 3 Pages 480-489  
  Keywords  
  Abstract The oxidation-reduction reaction of horse heart cytochrome c and cytochrome c (552, Thermus thermophilus), which is highly thermoresistant, was studied by temperature-jump method. Ferrohexacyanide was used as reductant. Thermodynamic and activation parameters of the reaction obtained for both cytochromes were compared with each other. The results of this showed that (1) the redox potential of cytochrome c-552,+0.19 V, is markedly less than that of horse heart cytochrome c. (2) [up triangle, open]Hox++ of cytochrome c-552 is considerably lower than that of horse heart cytochrome c. (3) [up triangle, open]Hox++ and [up triangle, open]Sred++ of cytoochrome c-552 are more negative than those of horse heart cytochrome c. (4) kred of cytochrome c-552 is much lower than that of horse heart cytochrome c at room temperature.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number refbase @ user @ Serial 3986  
Permanent link to this record
 

 
Author (up) Saigo, S. openurl 
  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  
Permanent link to this record
 

 
Author (up) Steinhoff, H.J.; Lieutenant, K.; Redhardt, A. openurl 
  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  
Permanent link to this record
 

 
Author (up) Steinhoff, H.J.; Schrader, J.; Schlitter, J. openurl 
  Title Temperature-jump studies and polarized absorption spectroscopy of methemoglobin-thiocyanate single crystals Type Journal Article
  Year 1992 Publication Biochimica et Biophysica Acta Abbreviated Journal Biochim Biophys Acta  
  Volume 1121 Issue 3 Pages 269-278  
  Keywords Animals; Crystallization; Horses; Kinetics; Methemoglobin/*chemistry; Solutions; Spectrum Analysis; Temperature; Thiocyanates/*chemistry  
  Abstract Association equilibria and association kinetics of the thiocyanate binding reaction to methemoglobin in single crystals and solution are studied using temperature-jump technique and polarized absorption spectroscopy. Different kinetic constants are found for the reaction in solution and crystal phase for the alpha- and beta-subunits of the methemoglobin tetramer. The reduction of the reactivity of the alpha- and beta-subunits in crystalline phase is 6-fold and 2.4-fold, respectively, compared to the values found in solution. The intramolecular binding reaction of the N epsilon of the distal histidine E7 which is observed in methemoglobin in solution cannot be detected in single crystals. Our results suggest that crystallization of hemoglobin has little influence on small-scale structural fluctuations which are necessary for ligands to get to the binding sites and large-scale structural motions are suppressed.  
  Address Institut fur Biophysik, Ruhr-Universitat Bochum, Germany  
  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:1627604 Approved no  
  Call Number Equine Behaviour @ team @ Serial 3800  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print