Presentation on theme: "Essential and trace ions"— Presentation transcript:
1 Essential and trace ions Ions with biochemical functions and have deficiency syndrume are :Iron and IodideIons studied are :iodide, copper,zinc,sulfur,chromium ,manganese,selenium, etc. ,iron
2 Iron :- First : Hemoproteins i – an electron carrier Iron functions in respiratory chain are :i – an electron carrierii- transport of molecular oxygenMost iron is associated with protiens:- First : Hemoproteinsresponsible for respiration Two group proteinsand for transport oxygen .
3 An respiratory Enzyme, where iron is complexed (a) Cytochrome – c :An respiratory Enzyme, where iron is complexedcovalently with the protein portion in a porphyrinring ( heme ring ) .Iron act as electron carrier by changing from ferrousto the ferric form and reversibly .Cytochrome –c role is in oxidation – reductionprocess of iron .
4 ( b ) Hemoglobin and myoglobin Hemoproteins which store and/or transportOxygen- Myoglobin :An oxygen carrying protein .. A single polypeptide with one oxygen binding siteBinds and releases oxygen through changes inoxygen conc. in sarcoplasma of skeletal muscle cells.
5 Hemoglobin Found in high conc. in red blood cells. It binds to oxygen in lungs and transports it to body cells, also transports CO2 from tissues to lungs.Hemoglobin has 4 protein chains ,each one has a heme ( porphyrin ring ) and ferrous iron .Iron complexes O2 by using its vacant pair of non bonding electrons .
6 Uptake and release of O2 is influensed by :- 1- The oxygen tension.2- PH3- Presence of 2,3 diphosphoglycerate .4- CO2 concenteration.Patients with iron-deficiency animia have : -a- Decreased capability for oxygen transport .b- Decreased in hemoglobin synthesis .
7 Iron storage and transport proteins Body handeling of iron requirments is by storage and transport proteinsa – The iron storage proteinsFound in liver, bone marrow and spleen.Ferritin : -A water soluble iron protein built up from apoferrtin and micelles of ferric hydroxide-phosphate complex.Iron is stored in ferritin as Fe3+ form and released as Fe2+
8 b – Iron transport proteins HemosiderinA water insoluble protein considered asa dehydrated form of ferritin.b – Iron transport proteinsTransferrinMajor protein in blood plasm synthesised by the liver, and it binds two ferric iron per molecule.Transferrin releases iron to blood red cells through receptor on red cell surface.
9 Daily iron requirements : - 10-12 mg for males 12-18mg for females 2- CO transferrin+Fe transferrin.Fe 3+.CO3( -2ransferrin.Fe3+ .co co Fe transferrin.2(Fe3+.co3Daily iron requirements : mg for males 12-18mg for femalesIron lost in human body through bile secretions, menstrual flow & other secretions. hemorrhage,Males lose o.6 mg iron dailyNon pregnent females lose 1.2 mg-1.8 mg iron dailyPregnent females lose 3-4 mg daily
10 Iron disteribution in normal adults Men WomenHemoglobin mg mgMyoglobin mg mgEnzymes (transport) mg mgFerritin( storage) mg mgTotal mg mg
11 Iron Absorption In food diet : - 1- Iron in liver and muscle is better absorbed than iron in eggs and vegetables , because iron is bond to phytate (inositol hexaphosphate ) .2 - Iron in hemoglobin is well absorbed , because it is still bond to porphyrin ring .3 - Iron in wheat , corn & black beans is relatively unavailable for body use .4 - Iron in ferritin is poorly absorbed , because the protein must firstly digested by G.I. proteases before absorption.5 - Released iron complexed with sugars ,ascorbic acid,citric acid and amino acids .
12 Absorption mechanismCooking food facilitate iron ligand breakdown increasing iron availability in gut.Low stomach PH allows reduction of ferric Fe3+ to ferrous Fe2+ with presence of reductant ( ? )Exess bicarbonate secreated by pencreas oxidises ferrous Fe2+ to ferric Fe3+Major iron absorption is in small intestine mostly in the duodenum .
13 Three hypothesis for absorption 1 – The mucosal blook hypothesis : -ApoferritinTransferrinApoferritinTo liver for storageFe3+Fe3+Fe3+Ferritin(H)(O)To bone marrow for useFe2+Fe2+Fe2+Fe2+Small intestineMucosal cellBlood
14 2 – Active transport hypothesis Endogenous ligandsFe 3+Fe 2+(H)(O)Biological energy compounds ATPFe 2+Fe 2+Fe 3+TransferrinmacromoleculesLumen of intestineMucosal cellBlood
15 3 – The ion-chelate hypothesis Endogenous ligandsStorageTransferrinFe2+Fe3+Fe-chelateFe-chelateFe3+R.B.CExcreationFerritin (storag )Lumen of intestineBloodMucosal cell