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Significance of biologically important elements (selection)

+
+
Na and K : Most important „free“ intra- and extracellular cations. Regulation of the osmotic
pressure, membrane potentials, enzyme activity, signalling.

2+
Mg : Chlorophyll; anaerobic energy metabolism (ATP → ATP).

2+
Ca : Signalling, muscle contraction, enzyme regulation. Main inorganic part of the
endoskeletons (bones, teeth, enamel: hydroxyapatite; Ca 5(PO 4) 3(OH)). Exoskeletons of
mussels, shells, corals, sea urchins etc: aragonite or calcite; CaCO 3).

I/II
V IV/V , Mo IV/VI , W IV/VI , Mn II/III/IV , Fe II/III , Ni I/II/III , Cu : active centres in electron-transport
(redox) enzymes, oxygenases, dismutases.

Fe and Cu: Transport of oxygen.

III
Fe : Iron-storage proteins (ferritins).

III
II
Fe + Fe in magnetite (Fe 3O 4): orientation of magnetobacteria, pigeons, bees in Earth’s
magnetic field.

Co: Synthases and isomerases (cobalamines, e.g. vitamin-B 12); methylation of inorganics.

2+
Zn : In the active centre of hydrolases, carboanhydrase, alcohol dehydrogenase, synthases;
genetic transciption (zinc fingers), stabilisation of tertiary and quartary structures of proteins;
repair enzymes.

IV
Si (“silicate“): Involved in the built-up of bones. In the form of SiO 2/silica-gels as support in
monocotyledonous plants (like grass) and the shells of diatoms.

V
P (phosphate): Constituent in hydroxi- and fluorapatite (Ca 5(PO 4) 3(OH/F)); energy
metabolism (ATP), NADPH, activation of organic substrate; phospholipids in cell membranes;
phosphate esters (DNA, RNA,…).

-II
Se : Selenocystein in special enzymes (e.g. glutathionperoxidase)

-
F : Fluorapatite (Ca 5(PO 4) 3F) in dental enamel

-
Cl : Along with hydrogencarbonate the most important free anion.

I: Constituent of thyroid hormones (such as thyroxine).

Medicinal relevant elements (selection):

+
Li : Treatment of bipolar disorder (maniac depression) and hypertension.

3+
Gd : Contrast agent in magnetic resonance tomography of soft tissues.

BaSO 4: Contrast agent for X-ray tomography. Sun protection.

99m Tc (a metastable γ-emitter; t 1/2 = 6 h): Radio diagnostics (bone cancer, infarct risk, …)