Figure 5.

Methionine oxidation of apolipoprotein A‐1 (apoA‐1) in high‐density lipoprotein (HDL). HDL was isolated by density/gradient‐ultracentrifugation of plasma from whole blood treated with Porphyromonas gingivalis (5 × 10⁷ colony‐forming units [CFU]/mL, at 37°C, 30 minutes) wild‐type strains ATCC or W50, with the gingipain mutants E8 (lacking RgpA and RgpB) and K1A (lacking Kgp) or without bacteria (Control). The ratio of oxidized/nonoxidized peptide intensities of methionine at amino acid positions 137 and 172 in apoA‐1 were calculated from the mass‐spectrum data obtained after separating isolated HDL by 2‐dimensional gel electrophoresis (2DE) and silver staining. Data are expressed as mean ± standard error of the mean (n = 3). met‐ox, methionine oxidation; mut, mutant