Capacity related characteristics of Glyco-Gel affinity chromatographic support.

We examined capacity related properties of "Glyco-Gel" (Pierce), a boronate agarose gel for separating and measuring glycated proteins by affinity chromatography. Our data indicate linear capacity to as much as 20 mg as applied hemoglobin or almost 10 mg as bound hemoglobin and 26 mg as applied serum proteins or a minimum of 2.5 mg as bound serum protein for each mL of gel. The capacity and affinity of the support for glycated proteins becomes optimum only after four regeneration cycles. The support matrix appears to have a small concentration of nonspecific binding sites equivalent to 0.09 to 0.18 mg as serum protein for each mL of gel. These sites do not bind hemoglobin. They lead to an overestimation of glycated protein that can cause large errors when the proportion of glycated protein is determined with small column loads. If near capacity loads are applied, the samples must be dialyzed or diluted to avoid decreased analytical recovery resulting from competitive and eluting properties of endogenous sugars.