Enzyme Modification and Oxidative Crosslinking using Carboxylate-, Phenol-and Catechol-Conjugated 1,8-Naphthalimides
Links to Fileshttps://onlinelibrary.wiley.com/doi/epdf/10.1111/php.13110
MetadataShow full item record
Type of Work41 pages
journal article post-prints
Citation of Original PublicationStacey Sova , Lisa A. Kelly , Enzyme Modification and Oxidative Crosslinking using Carboxylate‐, Phenol‐and Catechol‐Conjugated 1,8‐Naphthalimides, Photochemistry and photobiology, https://doi.org/10.1111/php.13110
RightsThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
This is the peer reviewed version of the following article: Stacey Sova , Lisa A. Kelly , Enzyme Modification and Oxidative Crosslinking using Carboxylate‐, Phenol‐and Catechol‐Conjugated 1,8‐Naphthalimides, Photochemistry and photobiology, https://doi.org/10.1111/php.13110, which has been published in final form at https://doi.org/10.1111/php.13110. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Access to this item will begin on April 16, 2020
Subjectsβ‐alanine, tyrosine and L‐dopa substituted 1,8 naphthalimides (NI‐Ala, NI‐Tyr and NI‐Dopa)
The ground‐ and excited‐state interactions of β‐alanine, tyrosine and L‐dopa substituted 1,8 naphthalimides (NI‐Ala, NI‐Tyr and NI‐Dopa) with lysozyme and mushroom tyrosinase were evaluated to understand the mechanism of oxidative modification. Photooxidative crosslinking of lysozyme was observed for all three conjugates. The yield was significantly reduced for NI‐Tyr and NI‐Dopa due to intramolecular electron transfer to the excited singlet state of the 1,8‐naphthalimide. Incubation of NI‐Tyr and NI‐Dopa with mushroom tyrosinase resulted in an increased fluorescence from the naphthalimide, suggesting that the phenol and catechol portion of the conjugates are oxidized by the enzyme. This results demonstrates that the compounds bind in the active site of mushroom tyrosinase. The catalytic activity of mushroom tyrosinase to oxidize both tyrosine (monophenolase) and L‐dopa (diphenolase) was modified by NI‐Tyr and NI‐Dopa. Monophenolase activity was inhibited and the diphenolase activity was enhanced in the presence of these conjugates. Detailed Michaelis‐Menten studies show that both Vmax and Km are modified, consistent with a mixed inhibition mechanism. Collectively, the results show that the compounds interact in the enzyme's active site, but also modify the distribution of the enzyme's oxidation states that are responsible for catalysis.