Cyclophosphazene-DNA Complexes

A stock solution of DNA was prepared by dropping a 10 nM solution of NaClO on the DNA fibers to give an approximate concentration of lmgml This solution was gently agitated at 4 °C for 48 h, centrifuged at 8000 r.p.m. for 10 min and its concentration determined spectrophotometrically. 

Cyclophosphazene compounds were dissolved just before use in 10 nM NaClO and added to DNA. The final DNA concentration was O.lOmgml and the reactions were run at room temperature in the dark for several days (2-5 days, depending on the compound). The different cyclophosphazene-DNA complexes corresponded to values of rj (number of cyclophosphazene molecules introduced per nucleotide) varying from 0 to 100 depending on the solubility of the drugs. 

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The association constants to a site (K) and the ratio (r) of bound EtdBr per nucleic acid phosphate were determined for the different cyclophosphazene-DNA complexes using Scatchard s method The number Of binding sites per base (n) for the non-complexed DNA has been found equal to 0.20 and the value of K to 1.2 X 10 M, in agreement with previously reported data and... 

UV Spectropkotometric Study of EtdBr Binding to Cyclophosphazene-DNA Complexes... 

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