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Essential and trace ions Ions with biochemical functions and have deficiency syndrume are : Iron and Iodide Ions studied are : iodide, copper,zinc,sulfur,chromium,manganese,selenium,

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Presentation on theme: "Essential and trace ions Ions with biochemical functions and have deficiency syndrume are : Iron and Iodide Ions studied are : iodide, copper,zinc,sulfur,chromium,manganese,selenium,"— Presentation transcript:

1 Essential and trace ions Ions with biochemical functions and have deficiency syndrume are : Iron and Iodide Ions studied are : iodide, copper,zinc,sulfur,chromium,manganese,selenium, etc.,iron 1

2 Iron functions in respiratory chain are : i – an electron carrier ii- transport of molecular oxygen Iron Most iron is associated with protiens :- First : Hemoproteins responsible for respiration Two group proteins and for transport oxygen. 2

3 (a) Cytochrome – c : (a) Cytochrome – c : An respiratory Enzyme, where iron is complexed covalently with the protein portion in a porphyrin ring ( heme ring ). Iron act as electron carrier by changing from ferrous to the ferric form and reversibly. Cytochrome –c role is in oxidation – reduction process of iron. 3

4 ( b ) Hemoglobin and myoglobin Hemoproteins which store and/or transport Oxygen - Myoglobin :. A single polypeptide with one oxygen binding site An oxygen carrying protein. Binds and releases oxygen through changes in oxygen conc. in sarcoplasma of skeletal muscle cells. 4

5 Hemoglobin Hemoglobin Found in high conc. in red blood cells. It binds to oxygen in lungs and transports it to body cells, also transports CO 2 from tissues to lungs. Hemoglobin has 4 protein chains,each one has a heme ( porphyrin ring ) and ferrous iron. Iron complexes O 2 by using its vacant pair of non bonding electrons. 5

6 Uptake and release of O 2 is influensed by :- 1- The oxygen tension. 2- PH 3- Presence of 2,3 diphosphoglycerate. 4- CO 2 concenteration. Patients with iron-deficiency animia have : - a- Decreased capability for oxygen transport. b- Decreased in hemoglobin synthesis. 6

7 Iron storage and transport proteins Body handeling of iron requirments is by storage and transport proteins a – The iron storage proteins Found 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 Fe 3+ form and released as Fe 2+ 7

8 Hemosiderin Hemosiderin A water insoluble protein considered as a dehydrated form of ferritin. b – Iron transport proteins Transferrin Major 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. 8

9 2 - C O transferrin+Fe 3+ transferrin.Fe 3+.CO 3 ( -2 ransferrin.Fe 3+.co co Fe 3+ transferrin.2(Fe 3+.co 3 Iron lost in human body through bile secretions, menstrual flow & other secretions. hemorrhage, Daily iron requirements : mg for males 12-18mg for females Males lose o.6 mg iron daily Non pregnent females lose 1.2 mg-1.8 mg iron daily Pregnent females lose 3-4 mg daily 9

10 Iron disteribution in normal adults Men Women Hemoglobin 3050 mg 1700 mg Myoglobin 430 mg 300 mg Enzymes (transport) 10 mg 6 mg Ferritin( storage) 750 mg 300 mg Total 4248 mg 2314 mg 10

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 ). 3 - Iron in wheat, corn & black beans is relatively unavailable for body use. 2 - Iron in hemoglobin is well absorbed, because it is still bond to porphyrin ring. 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. 11

12 Absorption mechanism Absorption mechanism Cooking food facilitate iron ligand breakdown increasing iron availability in gut. Low stomach PH allows reduction of ferric Fe 3+ to ferrous Fe 2+ with presence of reductant ( ? ) Major iron absorption is in small intestine mostly in the duodenum. Exess bicarbonate secreated by pencreas oxidises ferrous Fe 2+ to ferric Fe 3+ 12

13 Three hypothesis for absorption 1 – The mucosal blook hypothesis : - Fe 3+ Fe 2+ (H) Fe 2+ Fe 3+ Apoferritin (O) Ferritin Fe 2+ Fe 3+ Transferrin To liver for storage To bone marrow for use Small intestineMucosal cellBlood 13

14 2 – Active transport hypothesis Fe 3+ Fe 2+ Endogenous ligands macromolecules (H) (O) Biological energy compounds ATP Transferrin Lumen of intestine Mucosal cellBlood 14

15 3 – The ion-chelate hypothesis Fe 3+ Fe 2+ Endogenous ligands Fe-chelate Ferritin (storag ) Fe-chelate StorageTransferrin R.B.C Excreation Fe 3+ Lumen of intestine Mucosal cell Blood 15


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