title: Is arginine a protein-denaturant?
abstract: Arginine is a useful solvent additive for many applications, including refolding and solubilization of proteins from insoluble pellets, and suppression of protein aggregation and non-specific adsorption during formulation and purification. However, there is a concern that arginine may be a protein-denaturant, which may limit the expansion of its applications. Such concern arises from the facts that arginine decreases melting temperature and perturbs the spectroscopic properties of certain proteins and contains a guanidinium group, which is a critical chemical structure for denaturing activity of guanidine hydrochloride. Here, we show that although arginine does lower the melting temperatures of certain proteins, the extent is insufficient to cause denaturation of proteins at or below room temperature. The proteins described here show enzymatic activity and folded structure in the presence of arginine, although the local structure around aromatic amino acids is perturbed by arginine. Arginine differs from guandinine hydrochloride in the mode of interactions with proteins, which may be a primary reason why arginine is not a protein-denaturant.
authors.affiliation: Laboratory of Applied and Molecular Microbiology, Faculty of Agriculture, Kagoshima University, Korimoto, Japan.
authors.forename: Matsujiro
authors.initials: M
authors.lastname: Ishibashi
authors.forename: Kouhei
authors.initials: K
authors.lastname: Tsumoto
authors.forename: Masao
authors.initials: M
authors.lastname: Tokunaga
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ejima
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Kita
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Arakawa
mesh_terms: D024322:Amino Acids, Aromatic / Q000737:chemistry; D001120:Arginine / Q000737:chemistry*; D019791:Guanidine / Q000737:chemistry; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D013499:Surface Properties; D014364:Tryptophan / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry
chemical_list: D024322:Amino Acids, Aromatic; D014443:Tyrosine; D014364:Tryptophan; D001120:Arginine; D019791:Guanidine