Aggregation Suppression of Proteins by Arginine During Thermal Unfolding
Arginine has been used to suppress aggregation of proteins during refolding and purification. We have further studied in this paper the aggregation-suppressive effects of arginine on two commercially important proteins, i.e., interleukine- 6 (IL-6) and a monoclonal antibody (mAb). These proteins show extensive aggregation in aqueous buffers when subjected to thermal unfolding. Arginine suppresses aggregation concentration-dependently during thermal unfolding. However, this effect was not specific to arginine, as guanidine hydrochloride (GdnHCl) at identical concentrations also was effective. While equally effective in aggregation suppression during thermal unfolding, arginine and GdnHCl differed in their effects on the structure of the native proteins. Arginine showed no apparent adverse effects on the native protein, while GdnHCl induced conformational changes at room temperature, i.e., below the melting temperature. These additives affected the melting temperature of IL-6 as well; arginine increased it concentration-dependently, while GdnHCl increased it at low concentration but decreased at higher concentration. These results clearly demonstrate that arginine suppresses aggregation via different mechanism from that conferred by GdnHCl.
No Supplementary Data
Document Type: Research Article
Affiliations: Alliance Protein Laboratories,3957 Corte Cancion, Thousand Oaks, CA 91360, USA.
Publication date: 2006-09-01
More about this publication?
- Protein & Peptide Letters publishes short papers in all important aspects of protein and peptide research, including structural studies, recombinant expression, function, synthesis, enzymology, immunology, molecular modeling, drug design etc. Manuscripts must have a significant element of novelty, timeliness and urgency that merit rapid publication. Reports of crystallisation, and preliminary structure determinations of biologically important proteins are acceptable. Purely theoretical papers are also acceptable provided they provide new insight into the principles of protein/peptide structure and function.