Permeation of γ-globulin through microporous membranes in the presence of trace DNA

Permeation of gamma -globulin solution through three microfiltration membranes (Planova 35N (mean pore size (r) = 0.035 mum). Nucleopore(r = 0.1 mum) and Fluoropore(r = 0.1 mum)) was investigated. A drastic increase in flux was found with a decrease in DNA in the feed solution, which was normally contained in the protein solution as a contamination in the order of ppb. A DNA-gamma -globulin complex having a particle size of 135-225 nm was detected by dynamic light scattering measurements in the gamma -globulin solution, The DNA-gamma -globulin complex was destroyed by the addition of 0.4 mol/l NaCl in the gamma -globulin solution. The flux of the gamma -globulin solution through Planova 35N membranes drastically increased with the increase in NaCl concentration in the gamma -globulin solution up to 0.1 mol/l. This is explained bq: a decrease in the DNA-gamma -globulin complex in the presence of NaCl in the gamma -globulin solution. Only a slight increase in the flux of the gamma -globulin solution through Nucleopore membranes was found, on the other hand, a decrease in flux through the Fluoropore membranes was observed when the NaCl concentration in the feed solution of gamma -globulin increased. These results suggest that the effect of flux on the concentration of NaCl depends on the pore sizes and structure of the membranes and membrane materials, (C) 2001 Elsevier Science B.V. Ail rights reserved.