Electron Transfer Rates in Mitochondrial Proteins: Regulation and Specificity

McLendon, George; Zhang, Q.; Pardue, Kelli; Sherman, Fred; Corin, Alan F.; Ciacarelli, R.; Falvo, Joseph; Holzschu, Donald L.

doi:10.1007/978-1-4615-7482-8_15

Cited by 2 publications

(1 citation statement)

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“…The results are presented in Figure 2 in the form of Eadie-Hofstee plots. Preliminary results were previously reported by McLendon et al (1989). The initial velocities as a function of cytc(II) concentration were first fitted to monophasic kinetics using the Michaelis-Menten equation to obtain values of KM and the turnover number, Fmai/[e]0.…”

Section: Resultsmentioning

confidence: 99%

Effects of surface amino acid replacements in cytochrome c peroxidase on complex formation with cytochrome c

Corin¹,

McLendon²,

Zhang³

et al. 1991

Biochemistry

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Site-directed mutagenesis was employed to examine the role played by specific surface residues in the activity of cytochrome c peroxidase. The double charge, aspartic acid to lysine, point mutations were constructed at positions 37, 79, and 217 on the surface of cytochrome c peroxidase, sites purported to be within or proximal to the recognition site for cytochrome c in an electron-transfer productive complex formed by the two proteins. The resulting mutant peroxidases were examined for catalytic activity by steady-state measurements and binding affinity by two methods, fluorescence binding titration and cytochrome c affinity chromatography. The cloned peroxidases exhibit similar UV-visible spectra to the wild-type yeast protein, indicating that there are no major structural differences between the cloned peroxidases and the wild-type enzyme. The aspartic acid to lysine mutations at positions 79 and 217 exhibited similar turnover numbers and binding affinities to that seen for the "wild type-like" cloned peroxidase. The same change at position 37 caused more than a 10-fold decrease in both turnover of and binding affinity for cytochrome c. This empirical finding localizes a primary recognition region critical to the dynamic complex. Models from the literature proposing structures for the complex between peroxidase and cytochrome c are discussed in light of these findings.

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Section: Resultsmentioning

confidence: 99%