Ferritin cytochrome

Reverse transcriptase Hypothetical protein Ubiquitin Soma ferritin Cytochrome p450 NADH dehydrogenase Ribosomal proteins Transcription initation protein T ransposase Primosomal protein N ... 

Fig. 5. The approximate molecular mass determination of polygalacturonase [(0—0) - substrate 0.5% pectate, pH 4.6] and exopolygalacturonase [( — ) - substrate 1.0 pmol/ml of di(D-galactosiduronic) acid, pH 4.0] on Superose 12 column (FPLC device). Flow rate 0.5 ml/min. System 0.05 M phosphate buffer pH 7.0, 0.15 M NaCl. Standarts Ferritin (450 kDa), Katalase (240 kDa), Aldolase (158 kDa), Albumin (68 kDa), Albumin (45 kDa), Chymotrypsinogen A (25 kDa), Cytochrome C (12.5 kDa).

Iron is, as part of several proteins, such as hemoglobin, essential for vertebrates. The element is not available as ion but mostly as the protein ligands transferrin (transport), lactoferrin (milk), and ferritin (storage), and cytochromes (electron transport) (Alexander 1994). Toxicity due to excessive iron absorption caused by genetic abnormalities exists. For the determination of serum Fe a spectrophoto-metric reference procedure exists. Urine Fe can be determined by graphite furnace (GF)-AAS, and tissue iron by GF-AAS and SS-AAS (Alexander 1994 Herber 1994a). Total Iron Binding Capacity is determined by fuUy saturated transferrin with Fe(III), but is nowadays mostly replaced by immunochemical determination of transferrin and ferritin. 

From the standpoint of the relationship of almost all animal life, the transport of oxygen by heme (also written as haem in some literature) is the basis for respiration. Heme is one of several proteins that contain iron. Others include materials such as myoglobin, ferritin, transferritin, cytochromes, and ferrodoxins. In order to transport the oxygen required, the body of an average adult contains approximately 4 grams of iron. In species such as mollusks, oxygen is transported by proteins that contain copper instead of iron. These are sometimes referred to as the copper blues. The structure of heme is shown in Figure 22.19. 

The formation of nitric oxide in microsomes results in the inhibition of microsomal reductase activity. It has been found that the inhibitory effect of nitric oxide mainly depend on the interaction with cytochrome P-450. NO reversibly reacts with P-450 isoforms to form the P-450-NO complex, but at the same time it irreversibly inactivates the cytochrome P-450 via the modification of its thiol residues [64]. Incubation of microsomes with nitric oxide causes the inhibition of 20-HETE formation from arachidonic acid [65], the generation of reactive oxygen species [66], and the release of catalytically active iron from ferritin [67],... 

Iron occurs in every mammalian cell and is vital for life processes. It is bound to various proteins and found in blood and tissues. The iron-porphyrin or heme proteins include hemoglobin, myoglobin and various heme enzymes, such as cytochromes and peroxidases. Also, it occurs in non heme compounds, such as ferritin, siderophilin, and hemosiderin. Hemoglobin, found in the red blood cells, is responsible for transport of oxygen to the tissue cells and constitutes about two-thirds (mass) of all iron present in the human body. An adult human may contain about 4 to 6 grams of iron. 

The body iron is distributed mainly in two forms, one as haem in haemoglobin and cytochrome oxidase enzyme and other as iron bound to protein as storage compounds ferritin and hemosiderin, and as transport iron bound to transferrin. The total body iron in human adult is approximately 3.5 g out... 

The down-regulated proteins in HCC tissues have been identified. Park et al. identified aldehyde dehydrogenase 2 (25) and ferritin light chain (32). Kim et al. identified HSP 27, cathepsin D, and others (26). Lim et al. identified cytochrome B5, liver car-boxyesterase, and others (27). Li et al. identified SOD 1, aldolase B, and others (28). Fujii et al. identified galectin-1 (29). Kim et al. identified argininosuccinate synthase, carbamoyl-phosphate s mthase, and others (31). Table 1 shows the summary of the proteins whose expression was different between HCC cancer tissues and non-cancerous tissues. 

The possible role of the mycobactins in the storage of iron in the mycobacteria has been noted. Of greater significance is the identification of ferritin-like molecules in some bacteria. The cytochrome 6557.5 from Azotobacter vinelandii, known to be associated with large amounts of iron, is now known to be a ferritin, with an iron content of 13-20% and an electron-dense core of... 

Iron 3-5 g 10 mg (males) 18 mg (females) Electron transport (cytochromes), oxygen carrier (haemoglobin), storage/transport (ferritin), enzymes, immune system Widespread geographically fatigue, anemia Danger in hemochromatosis, Cooley s anemia, acute poisoning, Bantu siderosis... 

Deferoxamine is isolated from Streptomycespilosus. It binds iron avidly but essential trace metals poorly. Furthermore, while competing for loosely bound iron in iron-carrying proteins (hemosiderin and ferritin), it fails to compete for biologically chelated iron, as in microsomal and mitochondrial cytochromes and hemoproteins. Consequently, it is the chelator of choice for iron poisoning (Chapters 33 and 59). Deferoxamine plus hemodialysis may also be useful in the treatment of aluminum toxicity in renal failure. Deferoxamine is poorly absorbed when administered orally and may increase iron absorption when given by this route. It should therefore be administered intramuscularly or, preferably, intravenously. It is believed to be metabolized, but the pathways are unknown. The iron-chelator complex is excreted in the urine, often turning the urine an orange-red color. 

Iron-containing compounds in biological and clinical samples have been studied by separating them on chromatographic columns that were coupled to inductively coupled plasma mass spectrometers. Four iron-containing proteins, namely ferritin, haemoglobin, myoglobin and cytochrome-c were separated on a gel permeation column (Takatera and Watanabe, 1991). The absolute detection limits were 0.01-1 mg for the four proteins when 10 ml injections of samples were analysed. In other research, excess iron accumulations in human and animal... 

The mechanism of action of DFO is the formation of a stable complex with iron. It prevents the iron from entering into further chemical reactions, It is important that DFO chelates iron from hemosiderin and ferritin, but not from transferrin, It does not bind with the iron from hemoglobin and cytochromes. It is theorized that DFO is metabolized by plasma enzymes. The chelate is soluble in water and passed easily through the kidney (reddish color of urine). 

The majority of body iron is not chelatable (iron from cytochromes and hemoglobin). There are two major pools of chelatable iron by DFO (19). The first is that delivered from the breakdown of red cells by macrophages. DFO competes with transferrin for iron released from macrophages. DFO will also compete with other plasma proteins for this iron, when transferrin becomes saturated in iron overload. The quantity of chelatable iron from this turnover is 20mg/day in healthy individuals and iron chelated from this pool is excreted in the urine (19). The second major pool of iron available to DFO is derived from the breakdown of ferritin and hemosiderin. The ferritin is catabolized every 72 hours in hepatocytes, predominantly within lysosomes (I). DFO can chelate iron that remains within lysosomes shortly after ferritin catabolism or once this iron reaches a dynamic, transiently chelatable, cytosolic low-molecular-weight iron pool (20). Cellular iron status, the rate of uptake of exogenous iron, and the rate of ferritin catabolism are influent on the level of a labile iron pool (21). Excess ferritin and... 

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