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42 Cards in this Set

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What is the other name for vitamin K1?
Phylloquinone
What is one of the primary functions of Vit K?
Blood-clotting cofactor
What type of molecules compose the Vit K family?
Polyisoprenoid-substituded naphthylquinones
What exactly does Vit K do?
Functinos as a cofactor for post=translational modification of coag factors.
Which pathway is vit K-dependent?
Extrinsic
What is the function of Vit K in the extrinsic pathway?
Gamma-carboxylation Glutamic acid residues on Fx 2, 7, 9, 10
What enzyme is Vit K a cofactor for?
Y-Glutamylcarboxylase
Where does Y-Glutamylcarboxylase modify the Coag factors?
At 9-12 Glutamate residues on the N-terminal portions.
What else does Y-Glutamylcarboxylase act on other than clotting factors?
-Bone proteins
-Matrix proteins
How does the carboxylation of G-glutamyl residues activate clotting factors 2/7/9/10?
It allows them to bind to Phosphatidyl Serine on platelets thru a Ca2+ Bridge.
What are coag protein complexes composed of?
1. Proenzyme (Fx II or V)
2. Activator (IXa or Xa)
3. LMWBP (V or VIII)
What happens to Vit K during the y-carboxlation reaction?
It gets convered to an epoxide
What reduces the epoxide form of Vit K back to its original form?
Vit K Epoxide Reductase
What targets Vit K Epoxide Reductase?
Dicoumarol and Warfarin (anticoagulant drugs)
What are the 2 major symptoms of Vit K dficiency?
-Prolonged bleeding
-Easy bruising
3 Main general functions of Vitamin C:
1. Protein modification
2. Coenzyme
3. Antioxidant
3 Enzymes that Vit C acts as a cofactor for:
1. Prolyl Hydroxylase
2. Lysinyl Hydroxylase
3. Dopamine B-hydroxylase
What are Prolyl Hydroxylase
and Lysinyl Hydroxylase for?
Collagen post-translational modification
What is Dopamine B-hydroxylase for?
Norepinephrine synthesis.
How many electrons can Ascorbate accomadate as an antioxidant?
1 or 2
What 2 enzymes recycle oxidized Vit C?
1. Ascorbate Free radical reductase
2. Dehydroascorbic acid dehydrogenase
For which radicals is Vit C a scavenger?
-Singlet oxygen
-Peroxy radicals
-Superoxide
-Hydrogen peroxide
What metal element is Vit C essential for?
Iron - it reduces ferric iron to ferrous state.
What disease is caused by Vit C deficiency?
Scurvy
For which 3 physiological processes is Vit C essential?
1. Collagen synthesis
2. Tyrosine degradation
3. Catecholamine synthesis
What enzyme for Tyrosine degradation is Vit C used?
p-Hydroxyphenylpyruvate Dioxygenase
What transports IRON in the bloodstream?
Transferrin
How is iron stored?
As rust inside ferritin in the liver.
How many iron molecules are stored in the ferritin core?
Up to 4800
What enzymes contain iron-sulfur complexes?
-Aconitase (TCA cycle)
-Oxidases
-ETC enzymes
What are the important heme proteins (4)?
1. Hemoglobin
2. Myoglobin
3. Cytochromes
4. Aldehyde oxidase
What results from iron
-Deficiency
-Excess
Defic: anemia
Excess: hemosiderosis
What vitamins are antioxidants?
-B-Carotenes
-E
-C
What type of molecule is the Vitamin E family made up of?
Tocopherols (eight exist)
What is the most active for of Vitamin E?
a-Tocopherol
What is the primary antioxidant fuction of Vit E?
Prevention of oxidation of PUFAs in membranes by
-Molecular oxygen
-Free radicals
-Peroxides
What cells are especially protected by Vit E?
Erythrocytes
What recycles oxidized Vit E?
Vit C
Other than serving as an antioxidant what does Vit E do?
-Regulates enzymes
-Regulates gene expression
What enzymes are regulated by Vit E?
-Signal transduction enzymes
-Protein C kinase
-Phosphoprotein Phosphatase 2A
-Diacylglycerol kinase
-Lipoxygenase/Cyclooxygenase
What genes are regulated by Vit E?
-A-tropomyosin
-Scavenger receptors
What is the major effect of Vit E deficiency?
Fragility of RBCs