LIFESCI 3N03 Midterm: 3N03 M1 Iron

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Iron overview essential trace element for nearly every living organism highly abundant but it undergoes spontaneous aerobic oxidation to fe3+ -> low solubility at physiological ph precipitates as fe(oh)3 easily accepts or donates electrons. Fe2+ (ferrous) fe3+ (ferric) ferric iron is an oxidative reactant that generates hydroxyl radicals that are toxic iron is also more viable in this form. Ferric = highly reactive and potentially toxic hazardous radicals that can attack macromolecules and cause tissue injury - oxidate dna, protein/lipids. Fenton reaction: availability and reactivity regulated via its association with proteins prosthetic groups = non-polypeptide unit i. e. heme, fe-s cluster amino acids side chains i. e. histidine, tyrosine, etc. , in transferrin. Heme-containing proteins heme = iron-containing derivative of porphyrin has ferrous iron iron is in the middle of the 5 rings (porphyrin) examples: hemoglobin = oxygen carrier myoglobin = oxygen storage cytochromes = transport of electrons. Hb: 4 subunits - 4 heme groups (tetramer)