Deoxyribonucleic acid (DNA) is an important genetic substance in the organism, which plays a key role in cell proliferation, syn-thesis of proteins and transcription of genetic information in living cells [1]. The interactions of cationic porphyrins with nucleic acids have received considerable attention [2]. Several have clinical potential as anticancer agents in photodynamic therapy [3], probably as a consequence of their ability to selectively accumulate on the surface of tumor cells, become internalized, bind to genomic DNA, and then induce DNA strand cleavage. In this study, interaction of 5, 10, 15, 20-tetrakis (4-N-heptyl-pyridyl) porphyrin Copper (II) (CuTHPyP) with calf-thymus DNA was studied in tris buffer and low ionic strength at 27 °C by spectroscopic method. The binding constant K and the stoichiometric coefficient of CuTHPyP with DNA were evaluated. Multivariate curve resolution-alternating least squares (MCR-ALS) chemometrics method was applied to resolve the combined spectroscopic data matrix, which was obtained by the UV–vis method. Pure spectra of CuTHPyP and CuTHPyP–DNA complex, and their concentration profiles were then successfully obtained.
