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HYDROPEROXYNAPHTHALIMIDE DERIVATIVE‐MEDIATED OXIDATION OF LYSOZYME
Author(s) -
Yamamoto Takahiro,
Maeda Yasushi,
Matsugo Seitchi,
Kitano Hiromi
Publication year - 1995
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1995.tb08716.x
Subject(s) - lysozyme , chemistry , reagent , active site , fluorescence , radical , circular dichroism , enzyme , derivative (finance) , photochemistry , stereochemistry , organic chemistry , biochemistry , physics , quantum mechanics , financial economics , economics
— Lysozyme was photoirradiated in the presence of photo‐Fenton reagents (hydroperoxynaph‐thalimide derivatives) at 366 nm. Enzymatic activities of photoirradiated lysozymes were lower than that of native lysozyme. Taking account of the results of amino acid analysis and of fluorescence spectra, it was probably that Trp residues in the photoirradiated lysozyme were oxidized with hydroxyl radicals. The reagents formed complexes with lysozyme as proved by the inhibitory effects of the reagents on the enzymatic activities ( K 1 = 4.7 ± 1.2 × 10 4 M for HPO II, a hydroperoxide derivative of naphthalimide), which suggested that these reagents were bound to the active site cleft of lysozyme, and the Trp residues located in or near the active site cleft were photooxidized. Fluorescence‐difference spectra of photoirradiated lysozymes showed that Trp 62 was preferentially photooxidized. Furthermore, sodium dodecyl sulfatepolyacrylamide gel electrophoresis and circular dichroism spectra showed that the photooxidation examined here induced no significant change in the molecular size but a slight change in the conformation of lysozyme, which suggests the usefulness of the reagents in the site‐selective oxidation of biopolymers.