en Biological Sciences Biological Sciences Original Research: Basic Science in Medicine Original Research: Basic Science in Medicine In this study the effect of a methylated derivative of nitrogen mustard (mechloroethamin) on solubilized and reconstituted chromatin was investigated using UVNis spectroscopy, DNA and SDS gel electrophoresis and densitomeoic scanning techniques, The results indicated that the 210 and 260 nm absorbances of reconstituted chromatin were decreased in a dose-dependent manner after treatment with various concentrations of mechloroethamin. Alkylated chromatin showed difficulty in producing nucleosomes in comparison to the control, therefore a 50% reduction in absorbances was obtained. The amount of both core histone protein and DNA in the supernatant was decreased with increasing drug concentrations. It is suggested that mechloroethamin alters the interaction of ON A protein in the chromatin by producing cross-links between DNA and protein or protein and protein. Mechloroethamin, chromatin, reconslituted chromatin, core histone. 23 28 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-396&slc_lang=en&sid=1 MAHVASH KHODABANDEH 20031947532846005234 20031947532846005234 Yes From the Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Islamic Republic of Iran. AZRA RABBANI 20031947532846005235 20031947532846005235 No