FIG. 4.

Old yellow enzymes promote resistance to methyl vinyl ketone but not to 3-penten-2-one. (A) Cultures of wild-type (wt), oye2, oye3, and oye2 oye3 cells were grown to stationary phase and the A₆₀₀ was adjusted to 1, 0.1, or 0.01 before the cells were spotted onto plates containing MVK or 3-penten-2-one. Growth was monitored for 3 days, and results are shown for 1 mM MVK and 1.5 mM 3-penten-2-one. (B) Overexpression of OYE2 or OYE3 increases resistance to MVK but not to 3-penten-2-one. Wild-type strains containing vector (v), mcOYE2, or mcOYE3 were tested for sensitivity to MVK or 3-penten-2-one as described for Fig. 3. Chemical structures are shown for MVK and 3-penten-2-one.