Free radical inactivation of pepsin

✍ Scribed by Lj Josimović; I. Ruvarac; I. Janković; S.V. Jovanović

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 486 KB
• Volume: 43
• Category: Article
• ISSN: 0969-806X
• DOI: 10.1016/0969-806x(94)90176-7

✦ Synopsis

Alkylperoxy radicals containing one, two or three chlorine atoms, 'CO;, 0, '_ and HO, ' were reacted with pepsin in aqueous solutions. It was found that only Cl,COO' and 'CO; inactivate pepsin, attacking preferentially the disulfide bridge. Transient spectra obtained upon completion of the Cl,COO' + pepsin reaction at pH 5 indicate that 20% of initially produced C&COO radicals oxidizes tryptophan residues, and 40% disulfide bridges. The inactivation induced by the Cl,COO radical increases at lower pH, and the maximal inactivation, G,, = 5.8, was observed at pH 1.5. The inactivation of pepsin by 'CO; radicals depends on the absorbed dose. The maximal inactivation, G,, = 4.5, was determined in the dose range from 38 to 53 Gy.