Figure 1.

Hydrogen peroxide generation by crystallin derived peptides and β-amyloid peptide. A) Generation of H₂O₂ by αA66-80 peptide. αA66-80 peptide (1mg/mL) was incubated in 50mM phosphate buffer for different durations, up to 24 h. The sample was withdrawn every hour and H₂O₂ generation was monitored using Amplex red reagent. Closed circle, αA66-80 peptide; open circle, αA66-80pro. Inset shows the generation of H₂O₂ up to 24 h (avarage of three experiments). B) Relative amount of H₂O₂ generation by αA66-80 peptide, β-amyloid and α-crystallin. Assays were carried out in 50 mM phosphate buffer. H₂O₂ generation is presented in nano Molar scale. Data shown is the avarage of three independent experiments. H₂O₂ generation by αA66-80 peptide in the presence or absence of αA-crystallin or metal ion chelators or catalase is also shown in the figure. C) Comparision of H₂O₂ generation by LMW peptides isolated from 73-, 43- and 17-year-old human lenses. LMW peptides were isolated and assayed as described in methods section. The data obtained by Amplex red assay show a greater amount of H₂O₂ generation from LMW peptides of 73-year-old lenses. (The results shown are an avarage of three independent experiments.)