Figure 3.

Methionine sulfoxide content in yeast strains that were grown in the presence of hydrogen peroxide. Each yeast strain was grown generally in a synthetic medium lacking leucine and containing H₂O₂ (2 mM), as described in Fig. 1, until the cell density reached 150 Klett units in each cell culture. Cells were harvested and their extracts were measured for free methionine sulfoxide (A) or protein-bound methionine sulfoxide (B), as described in Materials and Methods. Black bars represent the wild-type parental strain, hatched bars represent the msrA null mutant strain, and dotted bars represent the overproducer strain.