Haem protein

Magnetic circular dicliroism (MCD) is independent of, and thus complementary to, the natural CD associated with chirality of nuclear stmcture or solvation. Closely related to the Zeeman effect, MCD is most often associated with orbital and spin degeneracies in cliromophores. Chemical applications are thus typically found in systems where a chromophore of high symmetry is present metal complexes, poriihyrins and other aromatics, and haem proteins are... 

Other non-haem proteins, distinct from the above iron-sulfur proteins are involved in the roles of iron transport and storage. Iron is absorbed as Fe" in the human duodenum and passes into the blood as the Fe protein, transferrin, The Fe is in a distorted octahedral environment consisting of 1 x N, 3x0 and a chelating carbonate ion which... 

Kaur, H., Fagerheim, L, Grootveld, M., Puppo, A. and Halliwell, B. (1988). Aromatic hydroxylation of phenylalanine as an assay for hydroxyl radicals application to activated human neutrophils and to the haem protein leghaemoglobin. Anal. Biochem. 172, 360-367. 

The oxidation of lipids can be promoted by transition metals, such as copper or haem proteins, by a process that... 

Transition metal- or haem protein-mediated oxidative or reductive decomposition. 

The accumulation of hydroperoxides and their subsequent decomposition to alkoxyl and peroxyl radicals can accelerate the chain reaction of polyunsaturated fatty-acid p>eroxidation leading to oxidative damage to cells and membranes as well as lipoproteins. It is well-recognized that transition metals or haem proteins, through their... 

Transition metals, or haem Proteins and Ruptured Erythrocytes and Myocytes... 

Injury to cells and tissues may enhance the toxicity of the active oxygen species by releasing intracellular transition metal ions (such as iron) into the surrounding tissue from storage sites, decompartmentalized haem proteins, or metalloproteins by interaction with delocalized proteases or oxidants. Such delocalized iron and haem proteins have the capacity to decompose peroxide to peroxyl and alkoxyl radicals, exacerbating the initial lesion. 

Thus the question arises as to what forms of haem proteins and transition metals are available in vivo that are capable of mediating the formation of damaging initiating or propagating species, since the majority of the iron and haem proteins in the human body are protected in vivo from exerting pro-oxidant activities by their compart-mentalization within their functional locations in the haem and non-haem iron-containing proteins and enzymes. 

In order to understand the potential for haem proteins to mediate the oxidative modification of LDLs, the interaction between ruptured erythrocytes (Paganga et al., 1992) and ruptured myocytes (Bourne etal., 1994) with LDL has been explored. Previous studies from this group have demonstrated that ferryl myoglobin radicals and ruptured cardiac myocytes, which generate ferryl myoglobin species on activation (Turner et al., 1990,... 

The handling of sulfate by protoaerobes depends upon the initial energised coupling to adenosine phosphate as APS, since sulfate is difficult to reduce. The reductase is a flavoprotein linked to Fe S electron transfer centres. Subsequently, released sulfite is reduced by a haem protein (SIR) in which haem is directly bound... 

Extended use but similar coordination chemistry of haem proteins from reductive to oxidative reactions. 

The cytochromes are another group of haem proteins found in all aerobic forms of life. Cytochromes are electron carriers involving a Fe(ii)/Fe(m) redox system. They are a crucial part of the electron transfer reactions in mitochondria, in aspects of the nitrogen cycle, and in enzymic processes associated with photosynthesis. 

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