scholarly journals Direct measurement of the self-exchange rate of stellacyanin by a novel e.p.r. method

1984 ◽  
Vol 218 (2) ◽  
pp. 609-614 ◽  
Author(s):  
S Dahlin ◽  
B Reinhammar ◽  
M T Wilson
Keyword(s):  
Exchange Rate ◽  
Exchange Reaction ◽  
Direct Measurement ◽  
Rate Constant ◽  
Close Agreement ◽  
Direct Methods ◽  
The Self ◽  
Blue Copper Protein ◽  
Copper Protein ◽  
Exchange Rate Constant

A method for reconstituting the blue copper protein stellacyanin with the stable copper isotopes 63Cu and 65Cu is reported. Small differences in the e.p.r. spectra of the two isotopic forms of stellacyanin have been used to monitor the electron self-exchange reaction of stellacyanin by rapid-freeze e.p.r. methods. The self-exchange rate constant (k11) for stellacyanin has been determined as 1.2 × 10(5) M-1 X S-1 at 20 degrees C. This value is in close agreement with values obtained from less-direct methods.

Cobalt, Iron and Ruthenium Complexes of Picolinic and Dipicolinic Acids: Syntheses, Solution Properties and Kinetics of Electron Transfer Reactions With Cytochrome C(II) and Some Inorganic Reductants

1989 ◽  
Vol 42 (1) ◽  
pp. 1 ◽  
Author(s):  
RM Ellis ◽  
JD Quilligan ◽  
NH Williams ◽  
JK Yandell
Keyword(s):  
Exchange Rate ◽  
Cytochrome C ◽  
Rate Constant ◽  
Order Rate Constant ◽  
The Self ◽  
Transfer Reactions ◽  
Solution Properties ◽  
Cobalt Iron ◽  
Exchange Rate Constant ◽  
Kinetics Of

Tris picolinate complexes of CO111 and RU111 have been synthesized, and their standard potentials measured (432 �10, 403 �2 mV) at 25�C and ionic strength 0.1 mol dm-3. The self-exchange rate constant of Ru ( pic )3O/- was found to be (1 .4 �0.9)×108 dm3 mol-1 s-l, from reaction with cytochrome C(II), Co( bpy )32+ and ~Co( phen )32+. For the reaction between Fe( dipic )2- and cytochrome ~(II), at 2S260C, pH 5.5 and I 0.1 mol dm-3 (KNO3), the second-order rate constant was (3.2 �0.l)×105 dm3 mol-1 s-1,with ΔH+ 19.9 �0.9 kJ mol-1 and ΔS+ -72.8 �.7 J K-1 mol-l. The self-exchange rate constant of Fe( dipic )2-/2- was reevaluated as (5.8 �0.2)×106 dm3 mol-l s-1.

Electron transfer in non-oxovanadium(IV) and (V) complexes: Kinetic studies of an amavadin model

2009 ◽  
Vol 81 (7) ◽  
pp. 1241-1249 ◽  
Author(s):  
Jeremy M. Lenhardt ◽  
Bharat Baruah ◽  
Debbie C. Crans ◽  
Michael D. Johnson
Keyword(s):  
Electron Transfer ◽  
Exchange Rate ◽  
Rate Constant ◽  
Exchange Process ◽  
Kinetic Studies ◽  
Electron Transfer Reaction ◽  
The Self ◽  
Synthetic Analog ◽  
Vanadium Complex ◽  
Exchange Rate Constant

Electron-transfer reactions of the eight-coordinate vanadium complex, bis-(N-hydroxyiminodiacetate)vanadium(IV) [V(HIDA)2]2–, a synthetic analog of amavadin with ascorbic acid and hexachloroiridate(IV), have been studied. The self-exchange rate constant for this analog has been calculated from oxidation and reduction cross-reactions using Marcus theory and directly measured using 51V NMR paramagnetic line-broadening techniques. The average self-exchange rate constant for the bis-HIDA vanadium(IV/V) couple equals 1.5 × 105 M–1 s–1. The observed rate enhancements are proposed to be due to the small structural differences between the oxidized and reduced forms of the HIDA complex and inner-sphere reorganizational energies. The electron-transfer reaction of this synthetic analog is experimentally indistinguishable from amavadin itself, although significant differences exist in the reduction potential of these compounds. This suggests that ligand modification effects the thermodynamic driving force and not the self-exchange process.

Determination of the Self-Exchange Rate Constant for Rusticyanin from Thiobacillus ferrooxidans and a Comparison with Values for Other Type 1 Blue Copper Proteins

1995 ◽  
Vol 34 (21) ◽  
pp. 5370-5374 ◽  
Author(s):  
Panayotis Kyritsis ◽  
Christopher Dennison ◽  
W. John Ingledew ◽  
William McFarlane ◽  
A. Geoffrey Sykes
Keyword(s):  
Exchange Rate ◽  
Rate Constant ◽  
Thiobacillus Ferrooxidans ◽  
The Self ◽  
Copper Proteins ◽  
Blue Copper Proteins ◽  
Blue Copper ◽  
Exchange Rate Constant

Pressure effect on hydrogen isotope exchange kinetics in chymotrypsinogen investigated by FT-IR spectroscopy

1991 ◽  
Vol 69 (11) ◽  
pp. 1699-1704 ◽  
Author(s):  
P. T. T. Wong
Keyword(s):  
High Pressure ◽  
Exchange Rate ◽  
Rate Constant ◽  
Bound Water ◽  
Pressure Effects ◽  
Protein Molecules ◽  
Fast Exchange ◽  
Exchange Rate Constant ◽  
Hydrogen Deuterium ◽  
Exchange Kinetics

Hydrogen/deuterium (H/D) exchange rate constants in chymotrypsinogen have been determined at several pressures up to 28.9 kbar by FTIR spectroscopy. The secondary structure of the protein molecules was monitored simultaneously at the corresponding pressures by the intensity redistribution of the infrared amide I band at these pressures. As in other proteins, the labile protons on the amide groups in chymotrypsinogen can, to a good approximation, be separated into two classes, each with distinct first order H/D exchange rates constants in the time period from 10 min to ~24 h. The fast exchange rate constant increases while the slow exchange rate constant decreases with increasing pressure. The increase in the fast exchange rate constant at high pressure is largely associated with the pressure-induced unfolding of the protein molecules. At extremely high pressure (12.8 kbar), in addition to the unfolding of protein molecules, pressure induced a distortion and weakening of the hydrogen bonds of the fold protein segments also contribute to an increase in the overall H/D exchange rate. The present results confirm that when chymotrypsinogen is dissolved in D2O, a considerable amount of D2O molecules is bound to the protein molecules on the surface as well as in the interior cavities of the molecules. The H/D exchange takes place between these bound D2O and the protons in the protein molecules. The mechanism of the H/D exchange and the interior dynamics in proteins are discussed on the basis of the present results. Key words: hydrogen/deuterium exchange, exchange kinetics, rate constant, pressure effects, infrared spectroscopy, protein, conformation structure, bound water.

Sign in / Sign up

Export Citation Format

Share Document