Aggregation and chemical reaction in hen lysozyme caused by heating at pH 6 are depressed by osmolytes, sucrose and trehalose

T. Ueda, M. Nagata, T. Imoto

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We examined the effects of osmolytes, sucrose and trehalose, on the deterioration of hen lysozyme as a model protein. Sucrose and trehalose depressed the aggregation of lysozyme molecules caused by heating at 100°C at pH 6. Since lysozyme was fully denatured under these conditions, the effects of sucrose and trehalose on the denatured state of lysozyme were investigated using reduced S-alkylated lysozyme, a model of denatured hen lysozyme. From analyses of circular dichroism spectra and fluorescence spectra, sucrose and trehalose were found to induce α-helical conformations and some tertiary structures around tryptophan residues in the reduced S-alkylated lysozyme. Moreover, these compounds also depressed chemical reactions such as deamidation and racemization, which often cause the deterioration of proteins, on the reduced S-alkylated lysozyme. Therefore, the data suggest that sucrose and trehalose have a propensity to depress such deterioration as the aggregation of protein molecules or chemical reactions in proteins by inducing some tertiary structures (including α-helical structures) in the polypeptide chain.

Original languageEnglish
Pages (from-to)491-496
Number of pages6
JournalJournal of biochemistry
Issue number4
Publication statusPublished - Jan 1 2001


All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology

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