Inactivation of Lysozyme in a Solution Containing Sodium Bisulfite under Scattered Light

• Published in: Chemical & pharmaceutical bulletin Vol. 35; no. 6; pp. 2519 - 2524
• Main Authors: NISHIDA, YUMIKO, MORITA, KUNIHIKO, ONO, TAKESHI, SHIMAKAWA, HARUMI
• Format: Journal Article
• Language: English
• Published: Tokyo The Pharmaceutical Society of Japan 1987; Maruzen; Japan Science and Technology Agency
• Subjects: aromatic amino acid; Biological and medical sciences; free radical; General pharmacology; Light; lysozyme; lysozyme inactivation; Medical sciences; Muramidase - antagonists & inhibitors; Muramidase - radiation effects; Pharmacology. Drug treatments; Physicochemical properties. Structure-activity relationships; scattered light; Scattering, Radiation; sodium bisulfite; storage solution; Sulfites; tryptophan; Autoxidation; Stability; Storage; Scattered light; Inactivation; Lysozyme; Solution
• ISSN: 0009-2363; 1347-5223
• DOI: 10.1248/cpb.35.2519

When a solution (pH 4.0) containing 1 mg/ml hen egg-white lysozyme (EC 3.2.1.17) and 1 mM sodium bisulfite (SBS) was stored at 3 °C under scattered light, the residual activity of lysozyme was reduced to about 10% within 3 d. The inactivation was dependent on the pH of the medium, and was especially marked at pH below 5. It was largely prevented by shielding the solution from light, by replacement of the dissolved oxygen in the medium by nitrogen gas and by the addition of several radical scavengers to the medium prior to storage. The absorbance of lysozyme treated with SBS for 3d under scattered light was decreased by about 10% at 280 nm, and the content of tryptophan residues of lysozyme was decreased by about 1.0 mol of Trp/mol of enzyme. The change in the state of aromatic amino acid residues of lysozyme treated with SBS under scattered light was observed by circular dichroism spectral analysis in the wavelength range of 250-340 nm, and this change was prevented by shielding from light and by addition of radical scavengers. These results suggest that the inactivation of lysozyme during storage in a solution containing SBS was due to modification or destruction of amino acid residues in lysozyme by free radicals formed during the autooxidation of bisulfite under scattered light.