Iron physiology

A Peptide Hormone Synthesized in Liver, Hepcidin, Coordinates Mammalian Iron Physiology... 

Wlien a strong electron-donor ligand such as pyridine is added to tlie reaction mixture, it can bond so strongly to tlie Rli tliat it essentially drains off all tlie Rli and shuts down tlie cycle it is called a catalyst poison. A poison for many catalysts is CO it works as a physiological poison in essentially the same way as it works as a catalyst poison it bonds to tlie iron sites of haemoglobin in competition witli O. ... 

Problems of iron metabolism with special reference to biochemical, physiological and clinical aspects. W. Keiderling and H. P. Wetzel, Angew. Chem., Int. Ed. Engl., 1966,5, 633-641 (82). 

Even more exciting was the discovery of bands at higher frequency (430-1600 cm ). Exchanging the sample in H2 0 resulted in a shift to lower frequency. A shift to lower frequency was also observed when the protein was enriched in Fe or Fe (Fig. 6). These data indicated the presence of an iron-oxo species. It was argued that this functionality may be related to the physiological function. 

Under physiologic conditions in the human adult, 1—2 X 10 erythrocytes are destroyed per hour. Thus, in 1 day, a 70-kg human turns over approximately 6 g of hemoglobin. When hemoglobin is destroyed in the body, globin is degraded to its constiment amino acids, which are reused, and the iron of heme enters the iron pool, also for reuse. The iron-free porphyrin portion of heme is also degraded, mainly in the reticuloendothehal cells of the liver, spleen, and bone marrow. 

Figure 38-4. Examples of three types of missense mutations resulting in abnormal hemoglobin chains. The amino acid alterations and possible alterations in the respective codons are indicated. The hemoglobin Hikari p-chain mutation has apparently normal physiologic properties but is electrophoretically altered. Hemoglobin S has a p-chain mutation and partial function hemoglobin S binds oxygen but precipitates when deoxygenated. Hemoglobin M Boston, an a-chain mutation, permits the oxidation of the heme ferrous iron to the ferric state and so will not bind oxygen at all.

Figure 50-4. Absorption of iron. is converted to Fe + by ferric reductase, and Fe " is transported into the enterocyte by the apicai membrane iron transporter DMTl. Fieme is transported into the enterocyte by a separate heme transporter (HT), and heme oxidase (FiO) reieases Fe from the heme. Some of the intraceiiuiar Fe + is converted to Fe + and bound by ferritin. The remainder binds to the basoiaterai Fe + transporter (FP) and is transported into the biood-stream, aided by hephaestin (FiP). in piasma, Fe + is bound to the iron transport protein transferrin (TF). (Reproduced, with permission, from Ganong WF Review of Medical Physiology, 21 st ed. McGraw-Hill, 2003.)...

Does the regulatory effect of iron, observed under laboratory conditions, have a physiological significance in the soft rot disease caused by E. chrysanthemi strain 3937 on AMcan violet ... 

Rice-Evans, C., Okunade, G. and Khan, R. (1989). The suppression of iron release from activated myoglobin by physiological electron donors and desferrioxamine. Free Rad. Res. Commun. 7, 45-54. 

Figure 7 Mixld for iron (Fe) deficiency induced changes in root physiology and rhizo-sphere chemistry associated with Fc acquisition in strategy I plants. (Modified froin Ref. 1.) A. Stimulation of proton extru.sion by enhanced activity of the plasnialemma ATPase —> Felll solubilization in the rhizospherc. B. Enhanced exudation of reductanls and chela-tors (carhoxylates. phenolics) mediated by diffusion or anion channels Pe solubilization by Fein complexation and Felll reduction. C. Enhanced activity of plasma membrane (PM)-bound Felll reductase further stimulated by rhizosphere acidificalion (A). Reduction of FolII chelates, liberation of Fell. D. Uptake of Fell by a PM-bound Fell transporter.

The PDOS of the iron in deoxy- and CO-myoglobin and of myoglobin with different degrees of water content was also determined by Achterhold et al. [112, 113]. They found that the modes with an energy larger than 3 meV (24 cm ) are harmonic at physiologically relevant temperatures. Those below 3 meV exhibit a... 

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