A solid support for affinity chromatography that covalently binds thiol groups via a cleavable connector arm

Abstract

Preparation of an agarose derivative (MPE-agarose) containing a maleimido group which is attached to agarose via a cleavable phenyl ester linkage is described. MPE-agarose was shown to react with the thiol groups in glutathione, bovine serum albumin, bovine hemoglobin, and yeast and rabbit muscle glyceraldehyde 3-phosphate dehydrogenase. Treatment of the resulting agarose-linked compounds for 10 min with 1 hydroxylamine (pH 7) resulted in the cleavage of the phenyl ester linkage, and release of the maleimido derivative of the compound from the gel. In the case of hemoglobin and glyceraldehyde 3-phosphate dehydrogenase noncovalent interactions between the gel and the released protein lowered the amount of protein which dissolved in the hydroxylamine solution upon cleavage of the phenyl ester linkages. Noncovalently absorbed protein could be removed from the gel, however, by washing the gel with 2 guanidine hydrochloride after treatment with hydroxylamine. Derivatives of MPE-agarose should prove useful in affinity chromatography and immunoabsorption where it is difficult to elute material bound to conventional affinity supports.