PORE-SIZE CONTROLLED AND AMINATED POLY(GAMMA-METHYL L-GLUTAMATE) PARTICLES FOR SELECTIVE REMOVAL OF NUCLEIC-ACIDS

This report describes a method for selective removal of nucleic acids from various protein solutions, using aminated poly(gamma-methyl L-glu tamate) (PMLG-NH2) particles. The adsorbing activity for nucleic acids (purified DNA from salmon spermary) increased with increase in either the amino-group content or pore-size (molecular mass exclusion of pol ysaccharide, M-lim) of the particles. The apparent dissociation consta nt between the DNA and the particles (amino-group content: 3.5meq g(-1 )) decreased from 8.2 x 10(-13) moll(-1) (M) to 2.0 x 10(-13) M with i ncrease in pore size from 2 x 10(3) to 2x10(5), at pH 7.0 and an ionic strength of mu=0.05. On the other hand, the adsorbing activity of bov ine serum albumin increased with increasing M,,, of the particles, but decreased with increasing ionic strength of the buffer. As a result, when M-lim was 2 x 10(3) and amino-group content was 3.5meq g(-1), PML G-NH2 particles removed DNA from various DNA-containing samples, such as protein solutions, at pH 7.0 and ionic strength (mu) of 0.2. The pa rticles also removed DNA from crude antigen solutions originating from Bordetella bronchiseptica and Pasteurella multocida. A high recovery of protective antigen (100%) was obtained with each sample solution af ter removal of the DNA, and the concentration of DNA in it decreased t o below 10 ng ml(-1).