Non-metalic Elements

Periodic Table bulk elements for some species trace elements

Halogenes Fluorine (F) Source: 1 mg F-/L seawater, CaF2, Na3AlF6 in soil Absorption: passive diffusion plasma: 0,15-0,20 mg/L tissues: 0,3-0,5 mg/kg bones: accumulation (!) increases resistance to dental caries

Chlorine (Cl) Cl- (predominant anion) - osmoregulation 115-120 mmol/L - granulocytes

Iodine (I) Uptake: Hypothyreosis: goiter - Hyperthyreosis

Thyroid hormones

NONMETALLIC ELEMENTS Boron (B) Borates in plants: - normal growth - infection resistance accumulated in algae, in sponges Arsenic (As) Arsenic (III) oxide: - poison carcinogenic Organic form of arsenic compounds are less toxic

Sulfur (S) Summary of sulfur functions: Good attacking and leaving group as R–S(-) (catalysis) Polymerizes to –S–S– As a base RS(-), S2- forms complexes with transition metals Thioethers, cyclic thioether formation

Selenium (Se) Oxidation states: -2, -1, 0, +2, +4, +6 Similar to S! Toxic (accumulation in plants!) Protective function: Pb2+, Hg2+, Cd2+ Essential microelement: Glutation peroxydase E–Se–H

The catalytic cycle of GSH peroxidase E – Se- E – SeOH E – Se – S – G ROH G – SH H2O H+, G – S – S – G ROOH, H+ The catalytic cycle of GSH peroxidase

Deficiency symptoms: muscular degeneration Keshan disease: weakness of heart muscle Glutathion peroxidase:

Silicon (Si) Terrestrial distribution: The most abundant element (next to oxygen) In vivo distribution: Data on its physiology are LIMITED Trace element in: - most higher animals - man Major element in: - many unicellular org. - in plants (grasses)

… – Gly – Ser – Ser – … SILICOSIS: (lungs) possible cross-linking of proteins

Cross-linking between collagen chains in lung tissue

Hypothetical model of silification

Nitrogen Occurrence: ~ 80% atmosphere NaNO3 salpeter Living: 1,4% (human body)

Biological Nitrogen Comes from N2 1011 kg of N2 fixed annually

1. Nitrogenase: dinitrogenase 12 - 14 mol ATP reductase 2. Ferredoxin (electron carrier!) Mo - Fe - protein+2 Fe - protein NITROGENASE

Bioinorganic importance of oxygen: Terrestrial distribution: 3rd of the most frequently occurring elements: (H, He, O2) 168O (99 %) 188O (izotóp) Bioinorganic importance of oxygen: ORGANOGENIC element

O2+ oxygen ion: no biological importance O oxygen atom: reactive (decomposition O3) O2- superoxide anion: UV, enzyme reactions (xanthinoxidase, NADPH-oxidase) O22- peroxide anion: dissociation of H2O2 OH hydroxy free radical: decomposition of H2O2 HO2 hydroperoxy free radical

Reduction of O2 to H2O e°(v)

Protection from superoxide and peroxide 1. Superoxide dismutase systems 2. Catalase (heme) 3. Peroxidase systems (heme) A

H2O2 + O2- superoxide radical O2 + OH- + ·OH hydroxyl radical O2 + free electron O2- superoxide radical H2O Physiological state superoxide dismutase H2O2 GSH glutathion peroxidase H2O catalase GSSG H2O H2O + O2 Pathological state Haber-Weiss’ reaction H2O2 + O2- superoxide radical O2 + OH- + ·OH hydroxyl radical Fenton’s reaction H2O2 + Fe2+ Fe3+ + OH- + ·OH hydroxyl radical