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Indian Journal of Biochemistry and Biophysics (IJBB) >
IJBB Vol.43 [2006] >
IJBB Vol.43(1) [February 2006] >
| Title: | Kinetics and mechanism of reduction of ferricytochrome c by glutathione and L-cysteine: A comparative study |
| Authors: | Subudhi, U
Chainy, G B N
Mohanty, P |
| Keywords: | Ferricytochrome c
Glutathione
L-cysteine
Reduction |
| Issue Date: | Feb-2006 |
| Publisher: | CSIR |
| IPC Code: | C07K14/80 |
| Abstract: | The kinetics and mechanism of the reduction of ferricytochrome c [Cyt c(III)] by substrates namely glutathione (GSH) and L-cysteine (L-cys) have been investigated spectrophotometrically employing [substrate]T >> [Cyt c(III)]T. The reaction exhibits first order dependence in [substrate]T and [Cyt c(III)]T. The pseudo-first order rate constant increases with an increase in pH, indicating that the conjugate base form of the HCyt c(III) is a better oxidant than the parent HCyt c(III). The electron transfer rate constants between the oxidants and GSH for both the k₁ and k₂ paths are found to be greater than that with L-cysteine. Hence, GSH is a better reductant of Cyt c(III) as compared to L-cysteine. A suitable mechanism has been proposed on the basis of experimental findings. The deprotonation constant for HCyt c(III) and the second order rate constants of k₁ and k₂ paths for the present reaction at 25ºC have been determined. |
| Page(s): | 37-40 |
| ISSN: | 0301-1208 |
| Source: | IJBB Vol.43(1) [February 2006]
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