Enhanced Protein Affinity and Selectivity of Clustered-Charge Anion-Exchange Adsorbents

• Published in: Analytical chemistry (Washington) Vol. 79; no. 23; pp. 9060 - 9065
• Main Authors: Fu, Joseph Y, Balan, Sindhu, Potty, Ajish, Nguyen, Van, Willson, Richard C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.12.2007
• Subjects: Adsorbents; Adsorption; Amino acids; Analytical biochemistry: general aspects, technics, instrumentation; Analytical, structural and metabolic biochemistry; Anion Exchange Resins - chemistry; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Ion exchange; Mutation; Proteins; Proteins - chemistry; Rodents; Thermodynamics; Performance evaluation; Anion exchange; Charge exchange; Adsorption; Calcium; Residue; Aminoacid; Adsorption capacity; Selectivity; Ion exchange; Protein; Chemical enrichment
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac070695n

In this work, we examined the possibility of improving ion-exchange adsorbent performance by nanoscale structuring of ligands into clusters of fixed size rather than a random distribution of individual charges. The calcium-depleted form of the protein α-lactalbumin, which displays a cluster of acidic amino acid residues, showed enhanced adsorption affinity and capacity on clustered-charge pentalysinamide and pentaargininamide adsorbents as compared to single-charge lysinamide and argininamide adsorbents of matched total charge. Two differently charge-clustered mutants of rat microsomal cytochrome b5, E11Q and E44Q, with the same total charge also were well differentiated by clustered-charge adsorbents. Thus, an organized rather than random distribution of charges may produce adsorbents with higher capacity and selectivity, especially for biomolecules with inherent charge clustering.