https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(07)60439-5.pdf

Wilson's Disease

Superoxide Dismutase: ORGANELLE SPECIFICITY

Publisher Summary This chapter discusses the methodology of circular dichroism (CD) and optical rotatory dispersion (ORD) data gathering and analysis in the rapidly changing field of protein structure, making use of synthetic polypeptide studies when necessary. ORD is the measurement, as a function of wavelength, of a molecule's ability to rotate the plane of linearly polarized light. CD is similar data evaluating the molecule's unequal absorption of right- and left-handed circularly polarized light. CD and ORD can yield useful estimates of protein secondary structure. Although all the amino acids except glycine contain at least one asymmetric carbon atom, most amino acids display only small ORD and CD bands. It is the conformation of the protein—that is, the asymmetric and periodic arrangement of peptide units in space, which gives rise to their characteristic ORD and CD spectra. In recent years, X-ray diffraction analysis has lead to the complete mapping of the peptide backbone and side-chain positions of lysozyme, several other enzymes, and quite a few other proteins in the solid state.

Circular dichroism and optical rotatory dispersion of proteins and polypeptides.

CHAPTER 6 – Oxygen Radicals, Hydrogen Peroxide, and Oxygen Toxicity

1. Physiology of Zinc: General Aspects.- 2. An Introduction to the Biochemistry of Zinc.- 3. Intestinal Absorption of Zinc.- 4. Promoters and Antagonists of Zinc Absorption.- 5. Systemic Transport of Zinc.- 6. Systemic Interactions of Zinc.- 7. Biochemistry of Zinc in Cell Division and Tissue Growth.- 8. Zinc in Cell Division and Tissue Growth: Physiological Aspects.- 9. Biochemical Pathologies of Zinc Deficiency.- 10. Zinc and Iron in Free Radical Pathology and Cellular Control.- 11. Zinc Status and Food Intake.- 12. Zinc and Reproduction: Effects of Deficiency on Foetal and Postnatal Development.- 13. A Note on Zinc and Immunocompetence.- 14. Zinc and Behaviour.- 15. Neurobiology of Zinc.- 16. Zinc in Endocrine Function.- 17. Severe Zinc Deficiency.- 18. Mild Zinc Deficiency in Human Subjects.- 19. Putative Therapeutic Roles for Zinc.- 20. The Diagnosis of Zinc Deficiency.- 21. Human Zinc Requirements.- 22. Dietary Pattern and Zinc Supply.- 23. Zinc Excess.- 24. The Biological Significance of Zinc for Man: Problems and Prospects.

Zinc in Human Biology

PCDD/F, PCB and PAH content of brazilian compost

A study on purified apo-erythrocuprein.

Cation exchange experiments were carried out on phlogopite, biotite, and muscovite using cryptand (222) as a complexing agent, dioxane as solvent, and Li as the exchanging cation. The results indicate greater than 90% exchange of the analyzed cations K +, Rb +, and Sr + + in phlogopite and biotite after two days. Similar results for the exchange in muscovite are observed but it is apparently slower. The amount of exchange observed for mica depends mainly on pH, time and the exchanging cation at a constant temperature. Residues of the mineral phase were also investigated by X-ray diffraction and a significant change of the interlayer spacing was detected. Some samples of the residue were analyzed for Li content. The compositions of the treated samples were in good agreement with the determined exchange of K §

The Cryptand [222] for Exchanging Cations of Micas

The preparation of apoferredoxin from spinach ferredoxin and ferredoxin of Clostridium pasteurianum with α,α′-dipyridyl without the addition of reducing agents is described.



Reconstitution to form active ferredoxins can be achieved in high yields under various conditions. 2-Mercaptoethanol can be replaced by cysteamine or Cleland's Reagent. The reconstitution is also possible by using elemental sulfur, cysteamine, and iron(II) ammonium sulfate. The origin of labile sulfur in Clostridial ferredoxin has been investigated. The elemental analyses show conclusively that in ferredoxin there are 5–6 additional sulfurs besides the 8 sulfurs from the cysteine moieties, while apoferredoxin contains only the 8 sulfurs of the cysteine groups. A clostridial [35S] ferredoxin has been prepared by using Na235S in the resynthesis. The uptake of sulfide corresponded to 6 equivalents of sulfur per mole of ferredoxin. Treatment of the 35S-labelled clostridial ferredoxin yielded apoferredoxin essentially free of radioactivity. From all of our analytical data the most probable formulation for Clostridium pasteurianum includes 8 equivalents of cysteine, 6 equivalents of labile sulfur, and 6 equivalents of iron.



The hydropersulfides of cysteamine and cysteine methylester were prepared in solution. Paramagnetic complexes with gav-values below 2 were prepared from the ferrous complex of cysteamine or cysteine methyl ester and hydropersulfides of cysteamine or cysteine methyl ester. The g -values of the persulfide complexes are 1.92, 1.94 and 2.00. The monomeric unit of these paramagnetic compounds is formulated as a disulfide-iron(II)-sulfide complex which is equivalent to a persulfide-thiolato-iron(II), and a sulfur complex of bis-thiolato-iron(II).



If one considers the active center in plant ferredoxin as an analogous dimeric unit and the center in clostridial ferredoxin as an oligomeric unit, the labile sulfur may be represented in the form of S2° or disulfide anion S22− in oxidized ferredoxins or supersulfide anion S2⋅− in reduced ferredoxins. Structures are postulated for the active center of binuclear plant ferredoxins that are in agreement with the chemical and physical properties. These contain Fe–S2–Fe groups which are believed to be non-planar and exhibit stereochemistry similar to that found earlier by X-ray analysis for the binuclear complex (CO)3FeS2Fe(CO)3. The oxidized binuclear ferredoxins are described by the valence resonance hybrids Fe(II)S2°Fe(II) and Fe(III)S22−Fe(III), and the reduced paramagnetic form by Fe(II)S2⋅−-Fe(II) and Fe(II)S22−Fe(III). This seems to unite different theories concerning the cause for the characteristic ESR signal of ferredoxins.



For polynuclear ferredoxins of the clostridial ferredoxin type an active center is suggested which contains units of binuclear ferredoxins in modified form. It appears that in the polynuclear active centers the formulation Fe(III)S22−Fe(III) participates more in the ground state. In the light of the chemical and physical properties it is proposed that in clostridial ferredoxin a multicenter three-dimensional iron-sulfur cluster exists rather than a pseudo-linear array.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1969.tb00492.x

Untersuchungen zur Struktur der Ferredoxine

The magnetic circular dichroism and circular dichroism spectra of xanthine oxidase are reported from 200–700 nm The magnetic circular dichroism spectrum exhibits weak bands at 520 and 375 nm which are assigned to the iron-sulfur and molybdenum chromophores, respectively The tryptophan chromophore gives a strong positive magnetic circular dichroism band at 292 nm and from the intensity of this band in xanthine oxidase, the presence of a total of 23–24 residues per molecule has been calculated

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1971.tb01580.x

Peter Krauss

Papers

PCDD/F, PCB and PAH content of brazilian compost

A study on purified apo-erythrocuprein.

The Cryptand [222] for Exchanging Cations of Micas

Untersuchungen zur Struktur der Ferredoxine

Investigation of xanthine oxidase. Magnetic circular dichroism studies.