potential studies on multiheme cytochromes

ELECTRON

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TRANSFER

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SIMULATION OF THE ELECTROCHEMICAL BEHAVIOR OF MULTIREDOX SYSTEMS - CURRENT/POTENTIAL STUDIES ON MULTIHEME CYTOCHROMES

C.Moreno’, A. Camposb, M.Teixeiraab, J. LeGall’, I.Mouraab, CVanDijk’ and J.J.G.Mouraab.

I.Montenegrod,

“Dept. Quimica, Universidade Nova de Lisboa, Portugal, bCTQB, Apt.127, 2780 Oeiras, Portugal, ‘Dept. Biochem., UGA, Athens, GA 30602, USA, ‘Dept. Quimica, Universidade do Minho, Portugal and ’ ATO, Wageningen, The Netherlands.

The direct unmediated cytochrome

electrochemical

response

of the tetrahemic

~3 [1] isolated from sulfate reducers (Desulfovibrio (0.) bacu-

latus (DSM 1743) and D. vulgaris (Hildenborough)

) was evaluated

us-

ing different electrode systems ( graphite (edge cut), gold, semiconductors (In02)

and mercury)

and different

tan-m-retry [cv] and differential gram was developed

[dpv]). A computer procv curve

in [2] and using a Gauss-Legendre

method

The experimental

center protein was deconvoluted

of the four mid-point

described deconvolution

(cyclic vol-

of a complete

cv curves and the four redox potentials

pH dependence

methods

simulation

of the integrals envolved.

for this multiredox generated

pulse voltamrnetry

for the theoretical

based on the method proposed for calculation

electrochemical

potentials

data obtained

using the theoretical were determined.

was evaluated

using the

method.

We acknowledge the support of INIC and JNICT. 1. JJ.G. Mom-a, C. Costa, M.Y. Liu, I. Moura and J. LeGall Biochim. Biophys. AC&Z(1991) in press. 2. R.S. Nicholson and I. Shain Anal. Chem. 36,106-723 (1964).

The