Fig. 1.

Schematic representation of pDNA cleavage activity by metHb. A) Hb tetramers (alpha and beta chains in red and orange color, respectively) interact with sc pDNA (red and blue strands) and convert it to open circular (oc) DNA by nicking. The ocDNA may be further cut into linear (L) DNA. B) Different isoforms of pDNA were observed after incubation with Hb (10 µM). The relative fraction of each isoform, as determined by agarose gel electrophoresis, was plotted against time and the gradual increase of ocDNA and LDNA , respectively, was monitored. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.).