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== Week 3 Tasks - Info for nickel(II) cyclam perchlorate ==

Properties of nickel(II) cyclam perchlorate

 * Molecular Formula: C10H24Cl2N4NiO8
 * Molar Mass: 457.915 g/mol
 * Melting Point: N/A
 * Boiling Point: N/A
 * Solubility in Water: N/A

nickel(II) cyclam perchlorate

Chemistry of ascorbic acid

nickel(II) cyclam perchlorate

Chemical Structure
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Quadratic Formula
$$\frac{-b\pm\surd (b^2-4ac)}{2a}

$$

Ferrichrome
Structure Ferrichrome is a cyclic peptide containing three glycine and three modified ornithine residues, with six oxygen atoms chelating to the Fe3+. Ferrichrome has a high Fe3+ binding constant, which can be explained by good hard-hard HSAB matching, as well as a strong chelate effect with the 6 oxygen donors, and a backbone that is able to pre-organize the donor to coordinate.

The affinity the Fe3+ complex has for ferrichrome is very high, due to the HSAB theory. Fe3+ is a hard metal ion, which binds strongly to the six oxygen ligand donors. It also has a strong chelate effect, as it is a hexadendate ligand, having six donor atoms with electron pairs that can be used to bond to a central metal ion, which then forms a ring. The ligand backbone conformation then pre-organizes the six donors, such that it holds them in position for the coordination of the Fe3+ atom.

Ferrichrome binds better to Fe3+ than other ligands, such as EDTA and tiron. Ferrichrome has 6 ligand donors, compared to the two from tiron, which is able to chelate stronger to the Fe3+. For EDTA, two of ligands are bonding to the iron ion are sp3 Nitrogen donors, which are intermediate donors, and do not bond well with the hard metal ion.

Biological Function of Ferrichrome
Ferrichrome is a Siderophore, which are metal chelating agents that have a low molecular mass and are produced by microorganisms and plants growing under low iron conditions. The main function of siderophores is to chelate ferric iron (Fe3+) from insoluble minerals from the environment and make it available for microbial and plant cells. Iron is important in biological functions as it acts as a catalyst in enzymatic processes, as well as for electron transfer, DNA and RNA synthesis, and oxygen metabolism. Although iron is the fourth most abundant element in the earth’s crust, bioavailability of iron in aerobic environments is low due to formation of insoluble ferric hydroxides. Under iron limitation, bacteria scavenge for ferric iron (Fe3+) by up-regulating the secretion siderophores in order to meet their nutritional requirements. Recent studies have shown that ferrichrome has been used as a tumor- suppressive molecule  produced by L. casei. The study from the Department of Medicine and Asahikawa Medical Univeristy, suggests that ferrichrome has a greater tumor-suppressive effect than other drugs currently used to fight colon cancer, including Cisplatin and 5-fluoro-uracil. Ferrichrome also had less of an effect on non-cancerous intestinal cells than the two previously mentioned cancer fighting drugs. It was determined that ferrichrome activated the C-Jun N-terminal kinases, which induced Apoptosis. The induction of apoptosis by ferrichrome is reduced by the inhibition of the c-jun N-terminal kinase signaling pathway.

Competition for Ferrichrome in Bacteria

Dissolved iron availability is essential for nearly all known life forms, however, bioavailability of iron is usually very limited. To overcome the problem of iron inaccessibility, bacteria compete with one another for bioavailable iron using siderophores. One of these methods involve certain organisms that have transporters for siderophores that are made by other organisms. An example of this is Pseudomonas Aeruginosa. Although P. Aeruginosa is able to use siderophores produced by the bacterium itself, pyvoverdine and pyochelin, it is also able to use Ferrichrome, which is a fungal siderophore, for the uptake of iron into itself. Ferrichrome is able to be transported across the outer membrane of the bacteria by the FiuA receptor, where the iron then becomes available for biological use in the cell. Another example of bacterium that use transporters to transport ferrichrome into the cell is Escherichia coli. E. Coli is unable to synthesize ferrichrome, but possesses a FhuA receptor for uptake of ferrichromes.