FSHN 3600 • Fat-Soluble Vitamins

Exam 3

Vitamin A & D exert a significant amount of their function by regulating ___ ___.

gene expression

Vitamin K functions as a ___ in the PTM of proteins.

cofactor

Vitamin A, E, & K exhibit structural similarity to ___ ___.

fatty acids

Vitamin A was the first “___ ___” discovered.

vital amine

Vitamin A compounds are referred to as ___.

Hint: the base molecule of vit. A is retinol.

retinoids

The structure of vitamin A is in a ___ configuration.

trans

Vitamin A

The most common retinyl ester consumed from animal sources is ___ ___. 

retinyl palmitate

Vitamin A obtained from plant sources is considered ___ ___, more specifically ___-___.

provitamin A, beta-carotene

Vitamin A

(T/F): Retinyl esters & carotenoids are included in the emulsification process of all dietary lipid & lipid-soluble compounds, eventually being encapsulated within micelles.

___ ___ is stored in the liver. ____ are stored in adipose tissue

Vitamin A, carotenoids

Vitamin A function

Visual cycle

Enters cell as retinol

Cell differentiation

Growth

Vitamin D deficiency

Rickets: soft bones, results from lack of vitamin D to promote adequate calcium absorption

The ___ of foods with vitamin D3 greatly reduced the incidence of rickets.

fortification

Vitamin E active form

alpha-tocopherol

Two major classes of vitamin E

tocopherols & tocotrienols

Vitamin E function

antioxidant

Vitamin E is associated with ___ __ __.

polyunsaturated fatty acids

Vitamin E absorption

Passive diffusion

From micelle to enterocyte & incorporated into chylomicrons for delivery to tissues.

Much of vitamin E is found in the ___ due to chylomicron remnants.

liver

VLDL contains ___-___, & serves as the one vehicle for distributing Vitamin E.

Most prominent protein for responsible for distributing vitamin E throughout the body is ___ - ___ ___ ___

alpha-tocopherol transfer protein

Antioxidant defense system prevents oxidative stress and consists of the following:

Vitamin C, vitamin E, GSH, riboflavin, & enzymes in redox reactions.

Vitamin E serves as a compound to eliminate ___ ___ & is referred to as a ___ ___ ___ because it donates the necessary electrons to the free radicals.

free radicals, free radical scavenger.

Vitamin E deficiency

hemolytic anemia

Vitamin K function

Cofactor for normal blood coagulation

PTM of specific proteins via γ-glutamyl carboxylation to activate them

Vitamin K active form

Hydroquinone form of vitamin K

Types of vitamin K

Plant sources: phylloquinone (K1)

Animal sources: menaquinone (K2)

Synthetic form: menadione (K3)

Vitamin K absorption

Delivered to micelle of enterocyte

• Phylloquinone is absorbed by active transport

• Menaquinone & menadione enter intestinal cells by passive diffusion

Incorporated into chylomicrons & delivered to the liver in chylomicron remnants & distributed to tissues via VLDL.

Vitamin K activates these 4 proteins for blood clotting. It requires a cofactor - reduced vitamin K, ____ ___ and enzymatic activity of vitamin K ____.

Protein II, VII, IX, X

dehydrovitamin KH₂

carboxylase

The ___ ___ ___ is an important part of blood clotting.

vitamin K cycle

Vitamin K deficiency is rare but those who are susceptible are

newborn infants & patients receiving antibiotics therapy for an extended time.

Newborns must receive a vitamin K shot because they can develop

Vitamin K deficiency bleeding (VKDB) that can result in brain damage & eventually death.

Vitamin K assessment

Measured by, seconds it takes the blood to clot from a sample.

Exceeding 25 s = deficient

Vitamin A is important in the:

visual cycle

growth

cell differentiation

reproduction

Vitamin D primary role

calcium homeostasis

Vitamin A & D are highly similiar because of how they

Regulate gene expression, serving as ligands for their specific nuclear receptors, which bind to specific DNA response elements present in promoter regions of specific genes.

Vitamin A derivatives are useful in

treatment of cancer & skin conditions, but are highly teratogenic

Vitamin D status has been linked to a number of autoimmune disease including

diabetes & multiple sclerosis