SIEVING STUDY OF CHROMATIN AND HISTONE-DNA COMPLEX BY POROUS HOLLOW-FIBER MEMBRANES

Permeation of chromatin isolated from human HeLa S3 cells and histone- DNA complex through regenerated cellulose hollow fibers was investigat ed as a model study of DNA removal for drug manufacturing using membra ne technology. It was found that the permeation of histone-DNA and chr omatin through the membranes having a mean pore diameter of 15 nm was substantially lower than the permeation of free DNA which did not comp lex with proteins based on the concentration determination of the feed and permeate solutions using UV spectroscopy. Direct observation to d etermine the existence of chromatin and histone-DNA complex in the per meate solution was also performed using atomic force microscopic imagi ng. No chromatin and chromatin-like structures were found in the exami nation of 10 areas of 1.0 x 1.0 mu m on the mica which had been adsorb ed from the solution permeated through the membranes. Thus, the membra nes having a mean pore diameter of 15 nm most likely reject the chroma tin and histone-DNA complex that are observed to have an apparent widt h of 25-30 nm based on atomic force microscopic imaging.