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Updated: Aug 9, 2026

Detection of Nitric Oxide and Superoxide Radical Anion by Electron Paramagnetic Resonance Spectroscopy from Cells using Spin Traps
Published on: August 18, 2012
[New method for measuring the distances between the nitroxide spin label and paramagnetic metal ions in
Abstract:
A new method of estimation of the distance RLM between the nitroxide spin label (NSL) and the paramagnetic metal ions (PMI), such as Co2+, Ni2+, Cu2+, Mn2+, VO2+, Cr3+, Fe3+ is suggested. The influence of the longitudinal relaxation time T1 of the PMI on the line shape of the NSL at 77 degrees K has been studied. It was found that the efficiency of the dipole-dipole interaction between NSL and PMI depends strongly on the T1 value of the PMI. Measurements of the RLM for 4 spin-labelled proteins (haemoglobin, nitrogenase, cytochrome P450 and Ca2+-dependent ATPase) by three various methods have proved the correctness of the new method and also its simplicity.
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