Synthesis of thiophilic adsorbents, containing amine spacer arms, and adsorption of immunoglobulins from adult bovine serum.
In order to remove immunoglobulins from adult bovine serum (ABS), adsorptions were carried out in suspension with thiophilic adsorbents without (T-gel) and with (ST-gels) short amine spacer. The developed ST-gels could be cleaned in sodium hydroxide and specifically adsorbed immunoglobulins from ABS at a lower ionic strength of the adsorption buffer than a T-gel. The ST-gels are suited for the performance of adsorptions in a suspension with a high concentration of the adsorbent. For an almost complete removal of immunoglobulins from ABS in 0.5 M potassium sulfate and 0.1 M potassium phosphate (pH 7), up to 75 g ST-gel per 1 suspension may process up to 100 ml ABS. The synthesized ST-gels contained an equal amount of amine spacers and sulfone groups. The ratio between coupled 2-mercaptoethanol molecules and sulfone groups was about 0.4. In comparison with the T-gel, the chemical stability of the ST-gels in solutions of 0.1 to 1 M sodium hydroxide was higher. The capacity for adsorbing pure immunoglobulins of the T-gel was 0.329 g g-1 (10.9 g l-1) and of the ST2-gel, 0.677 g g1 (52.3 g l-1). The capacity for adsorbing IgG from ABS of the T-gel was 0.177 g g1 (5.88 g l-1) and of the ST2-gel, 0.152 g g-1 (11.7 g l-1). This reduced capacity was attributed to a low affinity binding to the adsorbents of other proteins from ABS. When an incubation of the adsorbent with ABS was performed in 0.5 M potassium sulfate and 0.1 M potassium phosphate (pH 7), the affinity constant (Ka) for IgG of the T-gel was 2.5 x 10(6) M-1 and of the ST-gel, 3.1 x 10(7) M-1. In this adsorption buffer at a protein concentration above 5 g l-1, salt-promoted precipitation of IgG took place. When an adsorption was performed at the minimal ionic strength of the adsorption buffer, the Ka of the T-gel for IgG was about 9 x 10(3) M-1 and of the ST-gel, about 2.3 x 10(5) M-1. In this case, the removal of Igs from ABS was achieved by means of a partition equilibrium, rather than by high affinity adsorption.
Strouken
H P
HP
Department of Chemical Technology, University of Twente, Enschede, The Netherlands.
Veninga
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I
Bantjes
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D000588:Amines / Q000737:chemistry; D000818:Animals; D001798:Blood Proteins / Q000302:isolation & purification; D002021:Buffers; D002417:Cattle; D004355:Drug Stability; D005782:Gels; D007136:Immunoglobulins / Q000097:blood / Q000302:isolation & purification*; D007163:Immunosorbent Techniques; D007164:Immunosorbents / Q000138:chemical synthesis* / Q000737:chemistry; D012492:Salts; D012996:Solutions; D013450:Sulfones / Q000737:chemistry
D000588:Amines; D001798:Blood Proteins; D002021:Buffers; D005782:Gels; D007136:Immunoglobulins; D007164:Immunosorbents; D012492:Salts; D012996:Solutions; D013450:Sulfones