Vitamin k MUHAMMAD MUSTANSAR

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Vitamin k MUHAMMAD MUSTANSAR

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  3. 3. VITAMIN KAntihemorrhagic /coagulation vitamin orprothrombin factor.Two variants K1and,K2 .All are napthoquinone derivatives.
  4. 4. 4VITAMIN K (PHYLOQUINONE)It is essential for production of a type of proteincalled prothrombin & other factor involve inblood clotting mechanism. Hence it is known asanti – hemorrhagic vitamin.
  5. 5. • The basic structure of vitamin K is 1,4-naphtoquinone. Its vitamin activity dependson the methyl group in position two, whileits fat solubility and other properties are dueto the long side chains. Vitamin K2 is acollective term for menaquinones with sidechains of different lengths-always with aniso-prene unit attached.
  6. 6. 6FormsIt is available in 2 formsK1 – it is the form occurs in plant origin.K2 - is synthesized by intestinal bacteria.
  7. 7. • Phylloquinone (vitamin K1) is present invariable concentriations in the chloroplastsor green plants, where it is needed forphotosynthesis. Gram-positive bacteria,like certain strains of Escherichia coli andBacteriodes fragilis producemenaquinones (vitamin K2),
  8. 8. SOURCES• Cabbage• Cauliflower• Tomato• Alfa alfa• Spinach• Green leafyvegetables• Egg yolk• Meat• Liver• Cheese & dairy productsRDA: 70-140 microgm/day
  9. 9. Structure of vitamin K
  10. 10. 11ABSORPTION ,STORAGE, EXCRETIONABSORPTIONsmall intestineSTORAGE liver adipose tissueEXCRETION urine
  11. 11. BIOLOGICAL ACTIONS OF VITAMIN-K1. Vitamin-K is needed for formation ofproconvertin: It is needed for the formationof prothrombin. Deficiency of vitamin Kdecreases proconvertin level in blood.2. Vitamin-K modifies prothrombin: Vitamin-Kis a coenzyme in modification ofprothrombin to thrombin.
  12. 12. 3. Vitamin-K modifies other clotting factorsalso: Vitamin K is needed for maintenanceof normal levels of blood clotting factors II,VII, IX and X.
  13. 13. 3. Their conversion to biologically activeforms depends upon vitamin K. Theactivation involves carboxylation ofglutamyl residues in the molecules ofthese factors (including prothrombinalso) to form dicarboxylic glutamylresidue.
  14. 14. 4. Vitamin-K is needed for carboxylation ofglutamyl residue of Ca++binding transportbetween the flavin coenzyme and thecytochrome system.
  15. 15. FUNCTIONSFUNCTIONS• Vitamin K is essential for coagulation. Factors II(Prothrombin), VII (Proconvertin), IX(Christmas factor), X (Stuart Prower factor)• Proteins (Zymogens)»Post Translational modifications»Functionally active
  16. 16. Gamma Carboxylation of GlutamicGamma Carboxylation of Glutamicacidacid
  17. 17. 18FUNCTIONSit is essential for the hepatic synthesis ofcoagulation factor II, V, VII, IX, X.CLOTTING – it prevents hemorrhage only incases when there is defective production ofprothrombinOXIDATIVE PHOSPHORYLATION – itacts as a co- factor in oxidativephosphorylation associated with lipid
  18. 18. FACTORS CAUSING VITAMIN-KDEFICIENCY:• Surgical removal of intestine:• Liquid paraffin:• Antibiotic therapy for a long time:• Vitamin-K antagonists: Heparin and warfarin
  19. 19. long term administration of antibiotic doses formore than a week may temporarily suppressthe normal intestinal flora may causedeficiency of vit k
  20. 20. 21DAILY REQUIRMENTmen and women – 70 – 140 mcg.children – 35 – 75mcg
  21. 21. 22DEFICIENCYCausesDecreasesynthesis offactor 2,7,9,10 Increase clotting timeProlong bleedingHemorrhagicconditionsAfter antibacterialtherapy,Surgical operations-CholecystectomyConditions likeMalabsorptionObstructivejaundice
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  28. 28. Vitamin - K Deficiency• Deficiency causes:• Bleeding of gums• Dark circles under eyes• Bleeding
  29. 29. HYPERVITAMINOSIS KHemolytic anemia and jaundice (in largedoses)ANTAGONIST TO VITAMIN KHeparin, Dicumarol, Salicylates
  30. 30. Misuses• Prolonged consumption of megadoses ofvitamin K (menadione) results in anemia,which is a reduced level of red blood cellsin the bloodstream.

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