Oxidation of eugenol by purified human term placental peroxidase.
The oxidation of eugenol by purified human term placental peroxidase (HTPP) was examined. Spectral analyses indicated that, similar to horseradish peroxidase, HTPP is capable of catalyzing the oxidation of eugenol. The accumulated stable product in the reaction medium due to eugenol oxidation by HTPP was tentatively identified as quinone methide of eugenol (EQM). The EQM formation exhibited a pH optimum of 8.0 and was dependent on incubation time, amount of HTPP and the concentration of both eugenol and hydrogen peroxide. The specific activity of approx 2.8 micromoles of EQM/min/mg protein was observed with different preparations of HTPP. The EQM formation was significantly suppressed by glutathione and ascorbic acid. The classical peroxidase inhibitors viz. potassium cyanide and sodium azide blocked the reaction in a concentration manner. Collectively, the results suggest that eugenol may undergo peroxidative metabolism in human placenta.
Zhang
R
R
Florida Toxicology Research Center, Department of Environmental and Occupational Health, College of Public Health, University of South Florida, Tampa, Florida 33612-3805, USA.
Kulkarni
K A
KA
Kulkarni
A P
AP
D005054:Eugenol / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D006735:Horseradish Peroxidase / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000302:isolation & purification / Q000378:metabolism*; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet
D005054:Eugenol; D006735:Horseradish Peroxidase; D010544:Peroxidases