THE REMOVAL OF ENDOTOXINS FROM PROTEIN SOLUTIONS USING COLUMN PACKINGS WITH AMINATED POLY(GAMMA-METHYL L-GLUTAMATE) SPHERES

A method is described for the selective removal of endotoxins from var ious protein solutions using columns packed with aminated poly(gamma-m ethyl L-glutamate) (PMLG-NH2) spheres. The PMLG-NH2 adsorbents showed a high adsorbing activity for endotoxins which had an ionic strength o f mu = 0.05-1.0 and pH 5.0-9.0. The endotoxin-adsorbing capacity per m illilitre of the wet adsorbent increased from 0.40 to 1.35 mg (E. coli O111: B4 LPS) at mu = 0.2 and pH 7.0 while the amino-group content of the adsorbent increased from 0.8 to 3.5 meg g(-1). The PMLG-NH2-3.5 h as an amino-group content of 3.5 meq g(-1). This column packing select ively adsorbed endotoxins, without loss of the protein, from a gamma-g lobulin or cytochrome c solution which contained endotoxins at mu = 0. 05 and pH 7.0. On the other hand, when bovine serum albumin (BSA) was present in solution with endotoxins, both the endotoxins and the BSA w ere adsorbed by the column. The BSA-adsorbing activity increased with increasing amino-group content of the adsorbent. However, this undesir able adsorption was suppressed with increasing ionic strength of the b uffer. As a result, when the pa which had an amino-group content of 1. 5 meq g(-1) was used in conditions of mu= 0.2 and pH 7.0, the endotoxi ns were removed from a BSA-containing solution without affecting the r ecovery of the BA.