Iron Flashcards
(52 cards)
enhancers of iron absorption
sugars, acids, mucin, MFP factors
inhibitors of iron absorption
alkaline, polyphenols (tannins), oxalic acid (spinach), phytic acid (prefer Zn), phosvitin (egg yolk), divalent cations
functional iron is primarily ___ iron
heme (hemo/myoglobin, heme enzymes)
transport and storage iron is ___ iron
nonheme
transport iron is referred to as:
transferrin
storage iron is referred to as:
ferritin and hemosiderin
Heme= Fe + ?
porphyrin
heme synth made from ______ and needs ___ coenzyme
glycine/succinate; B6 (PLP)
3 stages of iron absorption
1) uptake at BBM 2) transport across cell 3) transport across BLM into plasma
2 forms of nonheme:
ferrous (highly reactive), ferric (unreactive)
hepcidin binds ___
ferroportin
____% heme absorbed, __% nonheme absorbed
3-8; 23
Fe2 is transported to BL by ligands such as ____; at BL it exits thru ____
mobilferrin; ferroportin
Fe2–>Fe3 in enterocyte by a copper containing enzyme called:
hephaestin
Fe3+ binds to ___
transferrin
hepcidin deficiency causes ____
hemochromatosis (too much iron in body)
hepcidin is ___ during infections/inflammation as host defense. Why?
elevated; limit available iron to invaders
hemosiderin is aggregated ___
ferritin (too much!)
Fe2+–>Fe3+ by ___
ferritin
plasma Fe–>____ –>RBC
marrow (make RBC heme)
uptake of iron into cells depends on ___
of TfRs
why is iron needed in cell?
cytochrome in mitochondria
Fe2+–>Fe3+ in all cells except enterocyte, needs this copper containing enzyme
ceruoplasmin
for every 1 mcg/L plasma ferritin, estimate there is ___mg Fe in storage
10
