I wanted to do UV -vis spectroscopy for DNA - metal binding study but I have found in most of the publications people have used CT-DNA. Why not isolate DNA from any cells and perform the assay ?
By CT-DNA I presume you mean calf thymus DNA? Cows are of course mammals so this is mammalian DNA. I think calf thymus has been a traditional source of DNA because one could get that tissue at slaughterhouses where cattle were butchered for meat, so it was a good source of tissue to make DNA and it was easy to extract DNA from the thymus.