Vit E Flashcards
What is the main form of Vit E
Tocopherols
How many forms of Vit E are there?
8 different forms
What are the general 2 groups that make up Vit E
Chromanol head group
Phytyl side chain
List the total 4 things that affect Vit activity
- Double bounds on the Phytyl side chain
- Configuration of 3 Chiral centers
- Esterification of the Head group
- location of Methyl groups on the phenolic ring
How to R groups affect Vit E activity
The more R groups the more active
How to double bonds on the phytyl side chain affect Vit E activity
The more the less active
What happens to groups esterified at the phenolic hydroxyl group during digestion
They get cleaved off and Vit E becomes active
How does Vit E enter the enterocyte and our systems
Passive diffusion into the enterocyte and incorporated into lymph
Repackaged into VLDL
Some transferred to HDL via ABCA1
What % of tocochromanols are absorbed
50%
Which transfer protein transports Vit E b/w membranes?
alpha-TTP (Tocopherol transfer protein)
- preferential to bind a-tocopherol
How is Vit E converted to hydrophilic metabolites
Tocopherol -w - oxidation
initiated by CYP-4F2
List the steps in Vit E breakdown
w-hydroxylation
oxidation
Truncation of phytyl side chain to 2-CEHC’s (4 rounds)
Conjugated to glucuronic acid/sulfate for urinary
Where is Vit E stored in the body?>
stored in membranes
90% in white adipose tissue (immobile)
Where is Vit E found in the body where it is readily available for redistribution
Liver and RBC
What is Vit E main metabolic function
to protect lipids and maintain membrane integrity by reacting as a free radical chain-breaking antioxidant
