earlier in the series (an inactive protein) (an active enzyme)
depend on vitamin
(A solid clot)
Function and Mechanism : Blood Clotting: A deficiency of vitamin K results in an increase in prothrombin time. The usual clinical manifestation is a tendency to hemorrhage.
Vascular Disease: Vascular smooth-muscle cells and arterial intima synthesize a matrix protein that undergoes a vitamin K-dependent carboxylation to become matrix gammacarboxyglutamic acid protein (MGP).
The pancreas, which makes insulin, is a site of synthesis
for certain vitamin K-dependent proteins.
Higher vitamin K status has been associated with lower fracture risks.
Vitamin K Cycle: - Vitamin KH2 is active form and K epoxide inactive form.
Dicoumarol and warfarin are antagonists of vitamin K.
Dicoumarol found in moldy sweet clover
Sweet clover disease
Why is newborn Vitamin K deficient ?
Maternal: cord blood ratio—30:1
Hepatic content in neonate-25% of adult.
Human milk content (2-15ug/l)-25% cow milk.
Colostrum rich in Vitamin K not given.
Plasma half-life-72 hrs.
Vitamin K: Who are at great risk of vitamin k deficiency?
Deficiency symptoms are:
Increase Clotting time
Bleeding gums and nose bleed.
Vitamin K – Deficiency:
Primary deficiency rare;
secondary deficiency occurs when fat absorption is impaired (e.g., cystic fibrosis, Crohn’s disease) or following long-term or high-dose administration of antibiotics (they kill the bacteria in large intestine)