Electron paramagnetic resonance cytochromes

Electron paramagnetic resonance (EPR) examination of hepatic microsomes from differently pretreated animals has lead to the conclusion that MC pretreatment leads to the formation of cytochrome P-1+50 (P-1+1+8) with high spin iron (6, 1+6). Chevion et al. (28) failed to demonstrate the presence of high spin cytochrome P-1+50 in a teleost fish even after induction with MC. The work of Chevion et al. (28 ) indicates further that the fish cytochrome P-1+50, which is inducible with PAH s and metabolizes readily PAH s, is not identical with the mammalian cytochrome P-1+1+8. 

Chevion, M., Stegeman, J.J., Peisach, J. and Blumberg, W.E. Electron paramagnetic resonance studies on hepatic microsomal cytochrome P- 50 from a marine teleost fish. Life Sci. (1977) 20, 895-900. 

Microsomal reduction of chromium(VI) can also result in the formation of chromium(V), which involves a one-electron transfer from the microsomal electron-transport cytochrome P450 system in rats. The chromium(V) complexes are characterized as labile and reactive. These chromium(V) intermediates persist for 1 hour in vitro, making them likely to interact with deoxyribonucleic acid (DNA), which may eventually lead to cancer (Jennette 1982). Because chromium(V) complexes are labile and reactive, detection of chromium(V) after in vivo exposure to chromium(VI) was difficult in the past. More recently, Liu et al. (1994) have demonstrated that chromium(V) is formed in vivo by using low-frequency electron paramagnetic resonance (EPR) spectroscopy on whole mice. In mice injected with sodium dichromate(VI) intravenously into the tail vein, maximum levels of chromium(V) were detected within 10 minutes and declined slowly with a life time of about 37 minutes. The time to reach peak in vivo levels of chromium(V) decreased in a linear manner as the administered dose levels of sodium... 

Zucchi MR, Nascimento OR, Faljoni-Alario A et al (2003) Modulation of cytochrome c spin states by lipid acyl chains a continuous-wave electron paramagnetic resonance (CW-EPR) study of haem iron. Biochem J 370 671-678... 

Peisach, J., Appleby, C.A., and Blumberg, W.E. (1972) Electron paramagnetic resonance and temperature dependent spin state studies of ferric cytochrome P-450 from Rhizobium japonicum, Arch. Biochem. Biophys. 150, 725-732. 

Scholes, C. P., Liu, Y., Fishel, L. A., Famum, M. F., Mauro, J. M., and Kraut, J., 1989, Recent ENDOR and pulsed electron paramagnetic resonance studies of cytochrome c peroxidase Compound I and its site-directed mutants, Israel J. Chem. 29 85fi92. 

BH4 = Tetrahydrobiopterin CAM = Cytotoxic activated macrophage cNOS = Constitutive nitric oxide synthase CPR = Cytochrome P450 reductase EDRF = Endothelial-derived relaxation factor EPR = Electron paramagnetic resonance spectroscopy IL-1 = Interleukin-1 iNOS = Inducible nitric oxide synthase EPS = Lipopolysaccharide, or endotoxin NMMA = ISp-monomethyl-L-arginine NOS = Nitric oxide synthase ROS = Reactive oxygen species SOD = Superoxide dismutase TNF = Tumor necrosis factor. 

Berthomieu C, Boussac A, Mantele W, Breton J, Nabedryk E. (1992) Molecular changes following oxidoreduction of cytochrome b559 characterized by Fourier transform infrared difference spectroscopy and electron paramagnetic resonance Photooxidation in photosystem II and electrochemistry of isolated cytochrome b559 and iron protoporphyrin IX-bisimidazole model compounds. Biochemistry 31 11460-11471. 

Abbreviations FAD, flavin adenine dinucleotide Fe-S, iron-sulfur proteins that can he identified in separate clusters by electron paramagnetic resonance analysis (the s-1, s-2 subscripts identify these iron-sulfur proteins as part of the succinate dehydrogenase complex) His, the histidine linkage between FAD and the large (70,000 daltons) protein moiety of the enzyme FMN, flavin mononucleotide N-la, N-2 subscripts identify these iron-sulfur proteins as part of the NADH-dehydro-genase complex UQ, ubiquinone Cyt bf and Cyt b, cytochrome b-566 and b-563, respectively. 

Fig. 3. Electron paramagnetic resonance absorption spectra of cytochrome c peroxidase and Compound ES at pH 7 and at 77°K (-------) enzyme and (—)...

T. lizuka, A. Nakagawa et at. (1997). Crystallization, preliminary diffraction and electron paramagnetic resonance studies of a single crystal of cytochrome P450nor. FEBS Lett. 412, 346-350. 

Tsubaki, M., Hiwatashi, A., Ichikawa, Y., and Hori, H. (1987). Electron paramagnetic resonance study of ferrous cytochrome P-450scc-nit oxide complexes Effects of cholesterol and its analogues. Biochemistry 26, 4527- 4534. 

CcP = Cytochrome c Peroxidase BCCP = Bacterial Cytochrome c Peroxidases APX = Soybean or pea or Tobacco Ascorbate Peroxidase MNP = Manganese Peroxidase LIP = Lignin Peroxidase EPO = Eosinophil Peroxidase LPO = Lactoperoxidase MPO = Myeloperoxidase TPO = Thyroid Peroxidase ARP = Arthomyces Ramos us Peroxidase SPO = Salivary Peroxidase PGHsynthase = Prostaglandin Hsynthase KatG = Catalase-peroxidase EPR = Electron Paramagnetic Resonance RR = Resonance Raman BHA = Benzhydroxamic Acid FA = Ferulic Acid DBNBS = 3,5-dibromo-4-nitrosobenzenesulfonic acid ABTS = 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) MNPr = Methylnitrosopropane INH = Isoniazid. 

GTP = 5 -guanosine triphosphate AE = Activating enzyme BAN = Backbone amide nitrogen BioB = Biotin synthase CD = Circular dichroism cyt = Cytochrome DFT = Density functional theory DMSO = Dimethylsulfoxide Dx = Desulforedoxin ENDOR = Electron-nuclear double resonance EPR = Electron paramagnetic resonance ESEEM = Electron-spin echo envelop modulation ETF = Electron transferring flavoprotein EXAFS = Extended x-ray absorption fine structure FAD = Flavin adenine dinucleotide Fd = Ferredoxin FMN = Flavin mononucleotide FNR = Fumarate-nitrate reduction FTIR =... 

Qu KB, Vaughn JL, Sienkiewicz A, Scholes CP, Fetrow IS (1997) Kinetics and motional dynamics of spin-labeled yeast iso-1-cytochrome c.l. Stopped-flow electron paramagnetic resonance as a probe for protein folding/unfolding of the C-terminal helix spin-labeled at cysteine 102. Biochemistry 36 2884—2897... 

Figure 4. Electron paramagnetic resonance spectra of neutrophil cytochrome b55g (b.245) Adapted from references 18, 24, and 32.

J.K. Hurst, T.M. Loehr, J.T. Curnutte, and H. Rosen, Resonance Raman and electron paramagnetic resonance structural investigations of neutrophil cytochrome b55g, /. Biol Chem. 266 1627 (1991). 

I. Ueno, S. Fujii, H. Ohya-Nishiguchi, T. lizuki, and S. Kanegasaki, Characterization of neutrophil b-type cytochrome in situ by electron paramagnetic resonance spectroscopy, FEBS Lett. 281 130... 

Zhang, C.S., T.C. HoUocher, A.R Kolodziej, and W.H. Orme-Johnson (1991). Electron paramagnetic resonance observations on the cytochrome c-containing nitrous oxide reductase from Wolinella succinogenes. J. Biol. Chem. 266, 2199. 

The first double bond inserted in an acyl chain is usually A9. The stearoyl-CoA A9 desaturase has been purified from rat liver (Strittmatter etal, 1974). This purification is extremely difficult because of the membranous and unstable nature of the desaturase. The terminal desaturase was found to be a single polypeptide of molecular weight 53 000 containing one atom of non-haem iron. Desaturase activity required NADH, stearoyl-CoA, oxygen, lipid and three proteins, cytochrome bs reductase, cytochrome bs and the desaturase. The cytochrome was the direct electron donor to the desaturase, which appeared (from EPR (electron paramagnetic resonance) studies) to utilize the iron in the oxidation/reduction sequence during desaturation of the fatty acyl substrate (Strittmatter et al, 1974). 

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