9. RDA for Vitamin K is…
Nutritional Requirement
70–140 μg of vitamin K per day
10. Absorption & Transport
Dietary vitamin K is absorbed
in the duodenum along with lipids.
It is transported to the liver
through chylomicron.
Stored in Liver
12. Functions of Vitamin K cont…blood
coagulation
• It is necessary for coagulation.
• It brings about the post translational
modification of certain blood clotting
factors. (factor II, VII, IX & X)
• They all are synthesized as inactive
zymogen form in the liver.
• Gamma carboxylation of glutamic acid
residues.
• These are the binding sites for calcium ions.
13.
14.
15. Functions of Vitamin K
Vitamin K is required for proper bone health
Bonehealth
•Vitamin K is also required for the
carboxylation of glutamic acid
residues of osteocalcin, a Ca2+
binding protein present in bone
Henrik Dam isolated vitamin K1 in 1929, while Edward Doisy isolated vitamin K2 in 1939.
Both of them were awarded Nobel prize in 1943.
In 1935 Danish scientist Henrik Dam described a fat-soluble factor that reduced bleeding in chicks fed an extremely low-fat diet. He named this factor vitamin K
is the only fat soluble vitamin with a specific coenzyme function
Green leafy vegetables are good dietary sources.
Even if the diet does not contain the vitamin, intestinal bacterial
synthesis will meet the daily requirements, as long as absorption is normal.
Factor II (prothrombin);
Factor VII (SPCA);
Factor IX (Christmas factor);
Factor X (Stuart Prower factor).
In normal adults dietary deficiency will not occurs since the
intestinal bacterial synthesis is sufficient to meet the needs
of the body.
This can result from obstructive jaundice, chronic pancreatitis, sprue, etc.
The newborns, premature infants have relative vitamin K deficiency.
This is due to lack of hepatic stores, limited oral intake
And absence of intestinal bacterial flora.
The newborns, premature infants have relative vitamin K deficiency.
This is due to lack of hepatic stores, limited oral intake
And absence of intestinal bacterial flora.
Warfarin and dicoumarol will competitively inhibit
the gamma carboxylation system due to structural
similarity with vitamin K.
Hence they are widely used as anticoagulants for therapeutic purposes.
