On-column entrapment of alpha-acid glycoprotein for studies of drug-protein binding by high-performance affinity chromatography.

Anguizola, Jeanethe; Bi, Cong; Koke, Michelle; Jackson, Abby; Hage, David

An on-column approach for protein entrapment was developed to immobilize alpha-acid glycoprotein (AGP) for drug-protein binding studies based on high-performance affinity chromatography. Soluble AGP was physically entrapped by using microcolumns that contained hydrazide-activated porous silica and by employing mildly oxidized glycogen as a capping agent. Three on-column entrapment methods were evaluated and compared to a previous slurry-based entrapment method. The final selected method was used to prepare 1.0 cm × 2.1 mm I.D. affinity microcolumns that contained up to 21 (±4) μg AGP and that could be used over the course of more than 150 sample applications. Frontal analysis and zonal elution studies were performed on these affinity microcolumns to examine the binding of various drugs with the entrapped AGP. Site-selective competition studies were also conducted for these drugs. The results showed good agreement with previous observations for these drug-protein systems and with binding constants that have been reported in the literature. The entrapment method developed in this study should be useful for future work in the area of personalized medicine and in the high-throughput screening of drug interactions with AGP or other proteins.

GLYCOPROTEINS; POROUS silica; HYDRAZIDES; PROTEIN-drug interactions; CAPPING proteins

Analytical & Bioanalytical Chemistry, 2016, Vol 408, Issue 21, p5745

1618-2642

Academic Journal

10.1007/s00216-016-9677-7