Surface-modified mutants of cytochrome P450(cam): Enzymatic properties andelectrochemistry

We report the electrochemistry of genetic variants of the haem monooxygenas e cytochrome P450(cam). A surface cysteine-free mutant (abbreviated as SCF) was prepared in which the five surface cysteine residues Cys-58, CSs-85, C ys-136, Cys-148 and Cys-334 were changed to alanines, Four single surface c ysteine mutants with an additional mutation, R72C, R112C, K344C or R364C, w ere also prepared, The haem spin-state equilibria, NADH turnover rates and camphor-hydroxylation properties, as well as the electrochemistry of these mutants are reported, The coupling of a redox-active label, N-ferrocenylmal eimide, to the single surface cysteine mutant SCF-K344C, and the electroche mistry of this modified mutant are also described. (C) 1999 Federation of E uropean Biochemical Societies.