en Biological Sciences Biological Sciences Original Research: Basic Science in Medicine Original Research: Basic Science in Medicine In this study calf thymus chromatin was fractionated into active (S1 and S2) and inactive (P 2) chromatin. Then the interaction of an anthracyc1ine antibiotic, adriamycin, with these fractions was investigated employing absorption and difference UV Nis spectroscopy and SDS and agarose gel electrophoreses. The results suggest that the binding of adriamycin to the S 1 fraction is slight but S2 and P 2 were considerably affected by drug action. In both cases the absorbances at 260 and 480 nm were decreased. As drug concentration is increased in the mixture, core his tones are aggregated and coprecipitate with the chromatin. The extent of condensation in P2 is higher when compared to the S2 fraction. Chromatin, Core histone, Adriamycin, Anthracycline. 305 310 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-379&slc_lang=en&sid=1 AZRA RABBANI 20031947532846004559 20031947532846004559 Yes From the Institute of Biochemistry and Biophysics, University of Tehran, Tehran MAHVASH JAFARI 20031947532846004560 20031947532846004560 No the Department of Biochemistry, Faculty of Medicine, Baghiatollah University of Medical Sciences, Tehran, I.R. Iran.