Figure 4.

FALS–SOD1 metalloenzymes retain variable degrees of free radical scavenging activity when copper is limited by the addition of a copper chelator. sod1Δcup1Δ (JS004) yeast harboring the PGK–SOD1 expression plasmids or vector alone (null) were diluted to a low density in rich media, the indicated level of BCS (a copper chelator) was added, paraquat (a free radical-generating drug) was added to 5 mM, and culture growth was measured spectrophotometrically after 48 hr. Values represent the average and range of two independent cultures in one experiment.