Mathematical approach for stopped-flow kinetics of fast second-order reactions involving inhomogeneity in the reaction cell

1974 ◽  
Vol 78 (3) ◽  
pp. 305-308 ◽  
Author(s):  
Chin-Tung Lin ◽  
D. B. Rorabacher
Keyword(s):  
Second Order ◽  
Stopped Flow ◽  
Mathematical Approach ◽  
Reaction Cell ◽  
Stopped Flow Kinetics ◽  
Kinetics Of

scholarly journals Kinetics of Reduction of Fe(III) Complexes by Outer Membrane Cytochromes MtrC and OmcA of Shewanella oneidensis MR-1

2008 ◽  
Vol 74 (21) ◽  
pp. 6746-6755 ◽  
Author(s):  
Zheming Wang ◽  
Chongxuan Liu ◽  
Xuelin Wang ◽  
Matthew J. Marshall ◽  
John M. Zachara ◽  
...  
Keyword(s):  
Redox Potential ◽  
Outer Membrane ◽  
Kinetic Data ◽  
Shewanella Oneidensis ◽  
Reorganization Energy ◽  
Second Order ◽  
Metal Species ◽  
Stopped Flow ◽  
Kinetics Of ◽  
Kinetics Of Reduction

ABSTRACT Because of their cell surface locations, the outer membrane c-type cytochromes MtrC and OmcA of Shewanella oneidensis MR-1 have been suggested to be the terminal reductases for a range of redox-reactive metals that form poorly soluble solids or that do not readily cross the outer membrane. In this work, we determined the kinetics of reduction of a series of Fe(III) complexes with citrate, nitrilotriacetic acid (NTA), and EDTA by MtrC and OmcA using a stopped-flow technique in combination with theoretical computation methods. Stopped-flow kinetic data showed that the reaction proceeded in two stages, a fast stage that was completed in less than 1 s, followed by a second, relatively slower stage. For a given complex, electron transfer by MtrC was faster than that by OmcA. For a given cytochrome, the reaction was completed in the order Fe-EDTA > Fe-NTA > Fe-citrate. The kinetic data could be modeled by two parallel second-order bimolecular redox reactions with second-order rate constants ranging from 0.872 μM−1 s−1 for the reaction between MtrC and the Fe-EDTA complex to 0.012 μM−1 s−1 for the reaction between OmcA and Fe-citrate. The biphasic reaction kinetics was attributed to redox potential differences among the heme groups or redox site heterogeneity within the cytochromes. The results of redox potential and reorganization energy calculations showed that the reaction rate was influenced mostly by the relatively large reorganization energy. The results demonstrate that ligand complexation plays an important role in microbial dissimilatory reduction and mineral transformation of iron, as well as other redox-sensitive metal species in nature.

scholarly journals Studies on tryptophan residues of Abrus agglutinin. Stopped-flow kinetics of modification and fluorescence-quenching studies

1987 ◽  
Vol 243 (1) ◽  
pp. 79-86 ◽  
Author(s):  
S R Patanjali ◽  
M J Swamy ◽  
A Surolia
Keyword(s):  
Amino Acid ◽  
Protein A ◽  
Stopped Flow ◽  
Amino Acid Residues ◽  
Acidic Amino Acid ◽  
Native Protein ◽  
Tryptophan Residues ◽  
Stopped Flow Kinetics ◽  
Two Phases ◽  
Kinetics Of

The presence of two essential tryptophan residues/molecule was implicated in the binding site of Abrus agglutinin [Patanjali, Swamy, Anantharam, Khan & Surolia (1984) Biochem. J. 217, 773-781]. A detailed study of the stopped-flow kinetics of the oxidation of tryptophan residues revealed three classes of tryptophan residues in the native protein. A discrete reorganization of tryptophan residues revealed three classes of tryptophan residues in the native protein. A discrete reorganization of tryptophan residues into two phases was observed upon ligand binding. The heterogeneity of tryptophan exposure was substantiated by quenching studies with acrylamide, succinimide and Cs+. Our study revealed the microenvironment of tryptophan residues to be hydrophobic, and also the presence of acidic amino acid residues in the vicinity of surface-localized tryptophan residues.

Absorbance and fluorescence stopped-flow kinetics of Rhus laccase and the catalytic reaction sequence

Biochemistry ◽  
1984 ◽  
Vol 23 (9) ◽  
pp. 2049-2056 ◽  
Author(s):  
Finn B. Hansen ◽  
Robert W. Noble ◽  
Murray J. Ettinger
Keyword(s):  
Catalytic Reaction ◽  
Stopped Flow ◽  
Reaction Sequence ◽  
Stopped Flow Kinetics ◽  
Kinetics Of

Stopped-flow kinetics of proton transfer involving cyclopentadiene derivatives

1978 ◽  
Vol 100 (19) ◽  
pp. 6162-6166 ◽  
Author(s):  
Tadashi Okuyama ◽  
Yoshiya Ikenouchi ◽  
Takayuki Fueno
Keyword(s):  
Proton Transfer ◽  
Stopped Flow ◽  
Stopped Flow Kinetics ◽  
Kinetics Of
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