Vitamin K Flashcards
Where does vitamin K get its name?
Named for Dutch word “koagulation”
What form makes up the majority of Vit K and where is it found?
Phylloquinone (K1) - plants
Where is menaquinone (k2) found?
Made by bacteria in LI. Animal products
Where are both K1 and K2 absorbed?
SI, mostly jejunum
How does K1 and K2 make it to the liver, and where does it go from there?
Packed into chylomicrons. Incorporated into VLDL
Where is the majority of Vitamin K stored?
Liver
Where is the remaining Vit K (not stored in liver) stored?
Heart, lungs, kidneys
T/F
Not much vitamin K is stored because it has a very long half life
False,
Not much is stored because it has a very short half life
What are the 3 categorical functions of Vitamin K?
Coenzyme
Blood clotting
Bone formation
Vitamin K adds a carboxylic acid to glutamate residues in specific proteins to make…
Carboxyglutamate
Carboxyglutamates are…?
Calcium-binding sites
Carboxyglutamates are implicated in what function?
Found on clotting factors. Required for clotting and bone formation
Osteocalcin (important in bone formation) is affected by what two vitamins, and how?
Synthesis stimulated by vit D
Carboxylated by vit K to facilitate Ca++ binding
What is the recommendation for Vit K to males and females respectively?
Adult males = 120 micrograms
Adult females = 90 micrograms
What 3 groups of people are most at risk for Vit K deficiency?
- ) Newborns (given vit K shots at birth to prevent bleeding in the brain)
- ) Patient with fat malabs disorders
- Patients chronically treated with antibiotics
