NUTR 3070 Lecture Notes - Lecture 12: Heme Oxygenase, Porphyrin, Ferrous
22 Jan 2020
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Document Summary
Functions in the body: oxygen transport (important for hemoglobin and myoglobin, redox reactions an active component of the etc, iron metalloenzymes. Ul = 45 mg/day leads to hemosiderosis. Heme iron: released from hemoglobin/myoglobin by proteases in the stomach and small intestine, heme is taken up in the small intestine by heme carrier protein 1 (hcp1, heme is taken to the intestine as a whole. Inside small intestine cells, the heme porphyrin ring is broken down by heme oxygenase into fe2+ and protoporphryin. Chelators small organic compounds that form complex with a metal ion: can affect iron absorption. Absorption is inhibited: examples of enhancers, vit c (acts as a reducing agent for ferric iron) and some soluble fibres (pectin, examples of inhibitors, polyphenols, oxalic acid and insoluble fibres. Iron is transported in the blood in the ferric form bound to transferrin (a carrier protein)
