VITAMIN K

1. VITAMIN K
Dr. Muhammad Sarfraz
M.B.B.S., M.Phil.(Pharmacology)
Senior Demonstrator
Quaid-e-Azam Medical College
Bahawalpur, pakistan.
1

2. Vitamin K
2

3. • VITAMIN ‘K’ IS A GROUP OF
STRUCTURALLY SIMILAR
FAT-SOLUBLE
VITAMINS
• Three Compounds Have
The Biological Activity Of
Vitamin K
3

4. • PHYLLOQUINONES
• MENAQUINONES
• MENADIONE
And
Menadiol Diacetate
4

5. 5

6. 6

7. • PHYLLOQUINONE
(vitamin K1 )
The Normal Dietary
Source
Green Vegetables
7

8. • MENAQUINONES
(Vitamin K2)
Synthesized
By
Intestinal Bacteria
8

9. • MENADIONE
• And
• Menadiol Diacetate
Synthetic Compounds
That Can Be Metabolized To
Phylloquinone
9

10. HUMAN BODY NEEDS vitamin K FOR
POSTTRANSLATIONAL
MODIFICATION
OF CERTAIN PROTEINS
REQUIRED FOR
BLOOD COAGULATION
10

11. HUMAN BODY NEEDS vitamin K FOR
The Synthesis Of
Osteocalcin
By
Osteoblasts
Of
Bone And Cartlage
11

12. Vitamin K1
PHYLLOQUINONE (K1)
An Important Chemical In
Green Plants
Functions As
An Electron Accepter
In Photosystem
During
Photosynthesis 12

13. Vitamin K1
Found In Large Quantities
In The
Photosynthetic Tissues
Of Plants
Green Leaves, And Dark
Green Leafy Vegetables
Spinach 13

14. Vitamin K1
Smaller Quantities In
Other Plant Tissues
Roots
Fruits
Etc 14

15. Vitamin K1
In Animals
Performs A Completely
Different Biochemical
Reaction
15

16. • DIETARY DEFICIENCY
EXTREMELY RARE
UNLESS
THE INTESTINE
(SMALL BOWEL)
WAS HEAVILY DAMAGED,
RESULTING
IN MALABSORPTION OF THE
MOLECULE. 16

17. DIETARY DEFICIENCY
DECREASED PRODUCTION OF K2
BY
NORMAL INTESTINAL MICROBIA
AS SEEN IN
BROAD SPECTRUM ANTIBIOTIC
USE
17

18. Deficiency Of Vitamin K In
The Newborn
Newborns
STERILE INTESTINES
Initially Lack The Bacteria
That Synthesize Vitamin K.
18

19. Deficiency Of Vitamin K In
The Newborn
Human Milk Provides
Only About
One Fifth
Of The Daily Requirement
For Vitamin K
19

20. Deficiency Of Vitamin K In The
Newborn
Recommended
That All Newborns
Receive A Single
Intramuscular Dose Of
Vitamin K As Prophylaxis
Against Hemorrhagic
Disease
20

21. Function of vitamin K
• Formation of
γ-CARBOXYGLUTAMATE (Gla)
• Vitamin K is required in
Hepatic Synthesis
OF
Blood Clotting Factors
II
(Prothrombin)
vii, IX, X 21

22. Function of vitamin K
Clotting Factors
Synthesized
As
Inactive Precursor
Molecules 22

23. Function of vitamin K
Formation of the clotting
factors
requires
vitamin ‘k’ dependent
carboxylation of glutamic
acid residues
to gla residues 23

24. Enzyme
Gamma Glutamyl
Carbxylase
24

25. 25

26. Function of vitamin K
• This forms a Mature
Clotting Factor that
• Contains Gla And Is
Capable Of Subsequent
Activation.
26

27. Function of vitamin K
•The Reaction
Requires O2 , CO2,
And The
Hydroquinone Form
Of Vitamin K
27

28. 28

29. 29

30. 30

31. ROLE OF Gla RESIDUES IN
OTHER PROTEINS
OSTEOCALCIN OF BONE
BONE MATRIX Gla
PROTEIN
31

32. OSTEOCALCIN
• Bone Gamma-carboxyglutamic
Acid-containing Protein
(BGLAP)
• Protein Hormone Found In
Bone And Dentin
• Secreted By Osteoblasts
32

33. OSTEOCALCIN
FUNCTIONS
• Bone Mineralization And Calcium
Ion Homeostasis
• Stimulating Beta Cells In
The Pancreas To Release
More Insulin
33

34. OSTEOCALCIN
FUNCTIONS
Directing Fat Cells To Release
The Hormone Adiponectin,
Which Increases Insulin
Sensitivity
34

35. OSTEOCALCIN
FUNCTIONS
• Acts On Leydig Cells Of
The Testis To
Stimulate Testosterone
Biosynthesis And Therefore
Affect Male Fertility
35

36. 36

37. 37

38. © 2008 Thomson - Wadsworth

39. Distribution and requirement of
vitamin K
• Vitamin K Is Found In
Cabbage
Spinach
Egg Yolk
Liver
39

40. Distribution and requirement of
vitamin K
• There Is Also Extensive
Synthesis Of The Vitamin By
The Bacteria In The Gut
• RDA For Vitamin K Is 120 Μ
G/Day For Adult Males And 90
Μg For Adult Females
40

41. 41