Cytochrome zinc-substituted

In the experiment, ZnCcP is produced by laser photolysis, then transient absorption spectroscopy follows the formation (k ) and decay (/Ceb) of ZnCcP + in wild-type and mutant crystals. Kang and Crane have studied the effects of interface mutations on electron transfer rates in single crystals using complexes between a zinc-substituted cytochrome c peroxidase (ZnCcP) and site-directed mutants of yeast cytochrome c (yCc).The mutants replaced the... 

An analogous approach has been applied to study the electron transfer reaction between yeast cytochrome c peroxidase (CCP) and cytochrome c (cyt c) by employing the complex between zinc-substituted CCP (ZnCCP) and native cyt c [70]. The two heme planes in this complex are nearly parallel at a metal-metal distance of 25 A and an edge-to-edge distance of 17-18 A. 

Electron phototransfer in zinc-substituted cytochrome c/cytochrome 65 complex [Zn(II)cyt c /Fe(III)cyt 65] has been studied [92]. Porphyrin rings lie parallel in this complex with the distances of ca. 8 A edge-to-edge, 18 A centre-to-centre. The Zn cyt c triplet excited state is quenched by Fe(III)cyt bn with the rate constant k = 5 x 105 s 1. Neither Fe(II)cyt b5 nor Zn(II)cyt quench TZn cyt c. 

Long range electron-transfer has also been demonstrated within the complex between zinc-substituted cytochrome c peroxidase and cyt c 59). The kinetics of intramolecular electron-transfer from Ru(II) to Fe(III) in ruthenium modified cyt c has also been investigated 58). 

Luminescence quenching of the zinc-substituted cytochrome c (Zn-cyt c) excited state by cytochrome b5 (cyt b5) has been investigated97. The most striking result of the quenching study is that the triplet emission decay rate of Zn-cyt c (3k = 102 s ) is remarkably accelerated in Zn-cyt c/cyt b5 (3k = 5 x 105 s-1) by about a factor of... 

H. Koloczek, T. Horie, T. Yonetani, H. Anni, G. Maniara, and J. M. Vanderkooi, Interaction between cytochrome c and cytochrome c peroxidase Excited-state reactions of zinc- and tin-substituted derivatives, Biochemistry 26, 3142-3148 (1987). 

Substitution of zinc(ll) ions into cytochrome c peroxidase (ZnCcP) has been used to exploit photoactivation of electron transfer (eT) reactions since the mid-1990s. The ZnCcP triplet state ( ZnCcP) reduces Fe(III) cytochrome c, and then back electron transfer recombines the charge separation to complete the catalytic cycle (see Figure 7.36). 

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