free radical

3-(2-Iodoacetamido)-2,2,5,5-tetramethyl-1-pyrrolidinyloxy, free radical
Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
MDL number:
PubChem Substance ID:
Pricing and availability is not currently available.


162-164 °C (lit.)

storage temp.


SMILES string




InChI key


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General description

3-(2-Iodoacetamido)-PROXYL is a free radical used as a spin probe in spin labeling techniques. This technique is helpful in investigating the dynamic aspects of molecular interactions of substances, proteins, lipids, and cell membranes.


25 mg in glass bottle


Sulfhydryl group specific spin label. Applications include study of ozone-treated human and bovine erythrocyte membrane proteins and the orientation of myosin subfragment on muscle fibers. DNA fragments containing phosphorothioate diesters can be labeled by spin labels.

Personal Protective Equipment

dust mask type N95 (US),Eyeshields,Gloves


NONH for all modes of transport

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Site directed nitroxide spin labeling of oligonucleotides for NMR and EPR studies
Shepherd NE, et al.
Tetrahedron, 71(5), 813-819 (2015)
Claire Bagnéris et al.
Nature communications, 4, 2465-2465 (2013-09-21)
Voltage-gated sodium channels have essential roles in electrical signalling. Prokaryotic sodium channels are tetramers consisting of transmembrane (TM) voltage-sensing and pore domains, and a cytoplasmic carboxy-terminal domain. Previous crystal structures of bacterial sodium channels revealed the nature of their TM...
First spin-labeled cytisine derivatives
Polienko YF, et al.
Chemistry of Natural Compounds, 49(2), 311-315 (2013)
J R Gillespie et al.
Journal of molecular biology, 268(1), 158-169 (1997-04-25)
Structural analysis of delta131delta, a fragment model of the denatured state of staphylococcal nuclease, has been extended by obtaining long-range distance restraints between protein chain segments based on paramagnetic relaxation enhancement methods. PROXYL spin labels were attached at unique cysteine...
Derek P Claxton et al.
Journal of molecular biology, 375(4), 1026-1039 (2007-12-08)
We have determined the structural changes that accompany the formation of a stable complex between a destabilized mutant of T4 lysozyme (T4L) and the small heat shock protein alpha-crystallin. Using pairs of fluorescence or spin label probes to fingerprint the...

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