[Study on the interaction mechanism of targeting molecules carboxymethyl polysaccharide with DNA].

The interaction of chitosan (CTS), carboxymethyl chitosans (CMCTS), and carboxymethyl cellulose (CMCL) with DNA was investigated through ethidium bromide (EB) as a sensitive fluorescence probe, and ultraviolet absorption spectra. The constant D can directly denote the degree of interaction of polysaccharide with DNA. The results indicated that the interraction sequence of biological polysaccharides with DNA is as follows: CTS>CMCTS>CMCL. The polysaccharides were mainly bound to DNA by intercalated binding, which resulted in fluorescence quenching effect of EB-DNA.