Peptide Inhibitor of Complement C1 Inhibits the Peroxidase Activity of Hemoglobin and Myoglobin

Figure 4

PIC1 and cysteine show similar inhibition of TMB oxidation that is reversible. (a) RBC lysates were incubated with increasing concentrations of PIC1 and L-cysteine. Samples were then combined with TMB and absorbance was read at 450 nm. Data are means of three independent experiments ± SEM. (b) RBC lysate (2.5 × 10⁸ cells/ml equivalents), 2 mg/ml metHb, or 2 mg/ml myoglobin was coated onto an Immunlon-2, 96-well plate, and incubated overnight. The plate was then washed and TMB added for 1 hour to promote oxidation. The oxidized material was then added to a fresh well containing either water or 2 mM PIC1. Samples were then measured by absorbance at 450 nm. Data are means of three independent experiments ± SEM.

(a)

(b)