Inositol iron binding

The structure of horse metHb has been determined at 2.0 A resolution. The increased resolution (c/. 5.5 and 2.8 A) is sufficient to show up a number of bound water molecules in the contact regions between the subunits which had been overlooked previously, but it is not, unfortunately, sufficient to decide whether the porphyrin rings are fiat or slightly domed, puckered or ruffled. The effects of pressure on the visible spectra of metHb and metMb have been reported (together with those of cytochrome c and horse radish peroxidase) the effect is to shift the equilibrium between open and closed crevice structures in favour of the latter. The spectrum of the short-lived intermediate formed in the reaction of eaq" with metHb is consistent with a low-spin iron(ii) species the rate of its subsequent transition to the stable high-spin derivative is solvent dependent. The results of a resonance Raman study on inositol hexaphosphate binding to metHb fluoride are consistent... 

Diets based on unleavened wheat bread contain a relatively large amount of phytic acid (inositol hexaphosphate), which can bind calcium, iron and zinc to form insoluble complexes that are not absorbed. Phytases in yeast catalyse dephosphorylation of phytate to products that do not chelate the minerals. 

In combination with choine, noatol prevents the fatly harden ing of arteries and protects the heart. symptoms are now being questioned because the exponhemal dels used were partially delicieni in certain other vitamins. Toxicitv-There is no known loxiciiy of inositol m animal cells, inasnol occurs as a component ol phospholipids. In plant cells, it is found as phytic aod. an organic acid that binds calaum. iron, and zinc in an insoluble complex and interferes widi their absorption. ... 

Substrate binding also affects the electronic structure of the fully oxidized diferric form of MIOX. Mossbauer spectroscopic data reveal the presence of two antiferromagnetically coupled high-spin Fe ions with a diamagnetic 5,ot = 0 ground state [387]. The addition of /wyo-inositol to the diferric enzyme perturbs the iron active site, but the binding mode is unknown. 

Xing G, Hoffart LM, Diao YH, Prabhu KS, Amer RJ, Reddy CC, Krebs C, Bollinger Jr JM. 2006. A coupled dinuclear iron cluster that is perturbed by substrate binding in /Myo-inositol oxygenase. Biochemistry 45 5393-5401. 

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