Significant Formation of 8-Hydroxydeoxyguanosine in Photoirradiation of “Photo-Fenton Reagent” with Calf Thymus DNA and L 5178Y cells

Abstract

A significant formation of 8-hydroxydeoxyguanosine (8-OHdG) was observed in photoirradiation of “photo-Fenton reagent” (1) with calf thymus DNA in maximum yield of 1.1%. The ten-fold enhancement of the formation of 8-OHdG compared to the control level was observed in photoirradiation of L5178Y cells with 1. The 8-OHdG formation well corresponds to the site specific DNA-cleaving activity of 1 upon photoirradiation.

Oxidation of feric‐cytochrome c by N, N′‐bis (2‐hydroperoxy‐2‐methoxyethyl)‐1,4,5,8‐naphthalene tetracarboxylic diimide, NP III ‐ site specific modification of cytochrome c

“…Wc havc previously carried out studies on hydroxyl radical mediated oxidation of salicylic acid, DNA, bovine serum alubumin (BSA) and low density lipoprotein [6][7][8][9][10][11][12] using NP III as the hydroxyl radical generator. The main advantage for the usage of NP III is the precision with which it can be used.…”

Hydroperoxynaphthalimide Derivative‐mediated Oxidation of Heme Proteins on Photoirradiation: Horseradish Peroxidase

“…Though native HRP weakly absorbed the irradiated light, the photoirradiation did not have a noticeable effect. Compound 1 has a role not only as a source of hydroxyl radicals but also as a strong electron acceptor (15)(16)(17)(18)(19)(20)(21)(22). After photoirradiation, the excited naphthalimide moiety of both 1 and 2 has the potential to abstract electrons from amines, alcohols and other reducing agents.…”

“…Therefore, DNA and some amino acid residues in proteins (His, Trp, Tyr, Cys, etc.) may undergo photoelectron transfer oxidation (15)(16)(17)(18)(19)(20)(21)(22). Thus, the extreme decrease in the absorption in the initial stage can be assigned to radical reaction, and the gradual decrease that was observed in HRP irradiated both in the presence of 1 and 2 may be due to energy transfer from the excited naphthalimide moiety or hydrogen abstraction by the naphthalimide moiety of the methyl ester derivative of 1 or 2 on photoirradiation.…”

“…1) on enzymatic activity and conformation and the interaction of 1 with a heme of the enzyme were investigated. This compound generates a highly reactive hydroxyl radical in high yield upon irradiation with near UV light (353 nm) (18)(19)(20)(21)(22)(23)(24)(25). This is in good contrast with conventional methods for generating hydroxyl radicals by using iron (11) (26,27) because the generation of hydroxyl radicals cannot be regulated by the latter methods.…”

“…In addition, because most biopolymers do not absorb around 353 nm and the energy of the excitation light is relatively low, unfavorable side effects may be excluded during experiments. It has been reported that 1 has oxidizing ability (28,29), can cleave DNA strands (20)(21)(22)24) and has antibacterial activity against Escherichia coli (gram-negative) and Brevibacterium (gram-positive) upon photoirradiation (18,19). Taking account of these advantages and abilities, the potential for use of 1 in the field of biochemistry and molecular biology is strongly anticipated.…”