Spin-trapping experiments for mechanistic studies
Our methodology rests on the fact that free radicals react with the nitroxide phosphorus compound, 5-diisopropoxy-phosphoryl-5-methyl-1-pyrroline-N-oxide (DIPPMPO), to form stable radical adducts, which are suitably detected and accurately quantified using 31P NMR in the presence of a phosphorus containing internal standard.
This system was thus applied to better understand the mechanism of enzymatic oxidation of linoleic acid by soybean lipoxygenases-1 (LOX). The total amount of radicals trapped by DIPPMPO was detected by 31P NMR at different experimental conditions. In particular the effect of dioxygen concentration on the amount of radicals being trapped was studied. At low dioxygen concentration, a huge increase of radicals trapped was observed with respect to the amount of radicals being trapped at normal dioxygen concentrations.
The DIPPMPO-based method could be subsequently used to shed light on other mechanisms involving radical species, including inorganic systems.
P. Giannì, H. Lange, C. Crestini
Lipoxygenase: unprecedented carbon-centred lignin activation.
ACS Sustainable Chem. Eng. 2018, in press.
C. Crestini, J. Marsh, G. Bianchetti, H. Lange
Identification and Quantification of Radical Species by 31P NMR-Based Spin Trapping — A Case Study: NH4OH/H2O2-Based Hair Bleaching.
Microchem. J. 2015, 121, 112–121.
L. Zoia, R. Perazzini, C. Crestini, D. S. Argyropoulos
Understanding the radical mechanism of lipoxygenases using 31P NMR spin trapping.
Bioorg. Med. Chem. 2011, 19, 3022-3028.
This system was thus applied to better understand the mechanism of enzymatic oxidation of linoleic acid by soybean lipoxygenases-1 (LOX). The total amount of radicals trapped by DIPPMPO was detected by 31P NMR at different experimental conditions. In particular the effect of dioxygen concentration on the amount of radicals being trapped was studied. At low dioxygen concentration, a huge increase of radicals trapped was observed with respect to the amount of radicals being trapped at normal dioxygen concentrations.
The DIPPMPO-based method could be subsequently used to shed light on other mechanisms involving radical species, including inorganic systems.
P. Giannì, H. Lange, C. Crestini
Lipoxygenase: unprecedented carbon-centred lignin activation.
ACS Sustainable Chem. Eng. 2018, in press.
C. Crestini, J. Marsh, G. Bianchetti, H. Lange
Identification and Quantification of Radical Species by 31P NMR-Based Spin Trapping — A Case Study: NH4OH/H2O2-Based Hair Bleaching.
Microchem. J. 2015, 121, 112–121.
L. Zoia, R. Perazzini, C. Crestini, D. S. Argyropoulos
Understanding the radical mechanism of lipoxygenases using 31P NMR spin trapping.
Bioorg. Med. Chem. 2011, 19, 3022-3028.