title: Why do solution additives suppress the heat-induced inactivation of proteins? inhibition of chemical modifications.
abstract: Thermoinactivation of proteins is prevented by several kinds of solution additives such as chaotropes, amino acids, amino acid derivatives, and polyamines. Here, we investigated the molecular mechanisms of action of the various additives that prevent thermoinactivation of bovine pancreatic ribonuclease A and hen egg white lysozyme. The thermoinactivation of both proteins in the presence of additives showed clear correlations with deamidation and β-elimination of the proteins. Thus, experimental evidences indicated that the effects of additives on thermoinactivation of proteins are highly due to the suppression of chemical modifications. To our surprise, not only the suppressive effect of the additives on heat-induced inactivation but also that on the chemical modification of proteins is remarkably similar by comparison of two unrelated proteins. This finding indicates the generality of the effects of additives on heat-induced chemical modification of proteins.
authors.affiliation: Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Tomita
authors.forename: Kentaro
authors.initials: K
authors.lastname: Shiraki
mesh_terms: D000818:Animals; D002417:Cattle; D006358:Hot Temperature; D009113:Muramidase / Q000737:chemistry; D011310:Preservatives, Pharmaceutical / Q000494:pharmacology*; D011489:Protein Denaturation / Q000187:drug effects*; D012259:Ribonuclease, Pancreatic / Q000737:chemistry
chemical_list: D011310:Preservatives, Pharmaceutical; D012259:Ribonuclease, Pancreatic; C421864:hen egg lysozyme; D009113:Muramidase