Interaction of lactoferrin with ascorbate and the relationship with bleomycin-dependent DNA damage

The interaction between bovine lactoferrin (bLf) and ascorbate (Asc) was investigated through malondialdehyde (MAD) formation in a solution containing DNA, bleomycin (BLM), and Fe2+ or Asc. The inhibition by bLf on MDA formation in the presence of Asc was not changed even by adding carbonate or oxalate ions to the solution. The percentage inhibition by the hydrolysates of bLf treated with pepsin, trypsin, and both enzymes on MDA formation was almost the same as that by the untreated bLf in the presence of Asc. The inhibition of MDA formation also occurred with the filtrate obtained from a solution containing bLf and Asc, but not with that from a solution of bovine serum albumin and Asc. The interaction of bLf and Asc was observed by gel filtration in a Sephadex G75 column. The binding amount of Asc was estimated to be 87 mol per mole of bLf.