Abstract: The present invention relates to in vitro and ex vivo methods of screening for modulators, homologues, and mimetics of lethal factor mitogen activated protein kinase kinase (MAPKK) protease activity, as well as methods of treating cancer by administering LF to transformed cells.

Abstract: A bacterial cell containing a functional cytochrome P450 monooxygenase system, said cell comprising a genetic construct capable of expressing a cytochrome P450 and genetic construct capable of expressing, separately from said cytochrome P450, a cytochrome P450 reductase, wherein each of the cytochrome P450 and the cytochrome P450 reductase have at their N-terminus a bacterial signal peptide. The cytochrome P450 and the cytochrome P450 reductase may be encoded by different constructs or the same construct. A bacterial cell containing a cytochrome P450 comprising a genetic construct encoding, and capable of expressing, said cytochrome P450 wherein the cytochrome P450 has, at is N-terminal, a bacterial signal peptide. The bacterial cells are useful as, for example, bioreactors, in drug testing and mutagenicity testing and as a source of cytochrome P450.