Quantitative determination and reversible modification of thiols using imidazolidine biradical disulfide label

The response of gypsy moth (Lymantria dispar L.) larvae infected with nuclear polyhedrosis virus to induced resistance in birch (Betula pendula Roth.)

“…The CAT activity was calculated from the rate of hydrogen peroxide decomposition mea sured spectrophotometrically at 240 nm (Wang et al, 2001). Measurement of the concentrations of thiol containing compounds was based on the fact that they are oxidized by 5,5 dithio bis (2 nitrobenzoic acid) (Khramtsov et al, 1997). The optical density was mea sured at 412 nm using cisteine as a standard.…”

In vivo Spectroscopy and Imaging of Nitroxide Probes

“…The approach is based on a dominant contribution of the GSH in the intracellular pool of fast-reacting thiols. The convenient time window of the reaction of the imidazolidine RSSR labels, R2SSR2 (Khramtsov et al, 1997) and 15 N-R2SSR2 (Roshchupkina et al, 2008) allows for quantitative measurement of GSH content by the analysis of their EPR spectral change kinetics. The kinetics approach looses the attractive simplicity of the static EPR measurements performed in vitro using fast-reacting R1SSR1 label but gains a decisive advantage by using low concentrations of the label compared to the GSH content.…”

“…Half a century of continuous progress in nitroxide chemistry has resulted in the design of specific NRs for spin labeling (Berliner, 1998), sitedirected spin labeling (Hubbell et al, 2000), EPR oximetry (Halpern et al, 1994;Swartz, 2004), pH (Khramtsov et al, 1982, thiols (Khramtsov et al, 1989(Khramtsov et al, , 1997, redox (Swartz et al, 2007) and NO measurements (Akaike et al, 1993;Joseph et al, 1993;Woldman et al, 1994). Over the past decade low-field L-band (1.2 GHz) EPR spectrometers and imagers have become commercially available allowing for functional EPR measurements in isolated organs (Komarov et al, 2012) and small animals such as mice Bobko et al, 2012).…”

A combined EPR and MD simulation study of a nitroxyl spin label with restricted internal mobility sensitive to protein dynamics

“…The bi-radical bis-(2,2,5,5-Tetramethyl-3-imidazoline-1-oxyl-4-yl) disulfide (RnSSRn) was developed in 1989 primarily for the quantitative determination of sulfhydryl (SH) groups using EPR (17)(18)(19). Since it reacts readily with the thiol side-chain of cysteine protein residues it has potential utility as a probe of motion although this has been little explored.…”