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40 Cards in this Set
- Front
- Back
Vitamin B6 was isolated by |
Khun & Szent-Gyoryi |
|
RDA for B6 |
1.3mg/day |
|
How many forms of B6 are ther |
6 |
|
Stablest of the B6 compounds mainly found in animal foods |
Pyridoxine |
|
Main B6 forms found in plant foods |
Pyridoxal and Pyridoxamine |
|
Absorption of B6 requires |
dephosphorylation |
|
_____ at the brush border remove phosphate groups for absorption of B6 |
Phosphotases |
|
B6 is absorbed into the liver via what transport at physiological conditions |
Passive diffusion |
|
Main organ that takes up B6 |
Liver |
|
Main form of B6 in the blood that binds to albumin |
PLP |
|
Only unphosphorylated vitamers can be taken up by the |
Tissues |
|
Most of B6 is stored in what? |
Muscle |
|
Coenzyme form of B6 |
PLP |
|
______ prevents the diffusion of the vitamin out of the cells |
Phosphorylation |
|
What prevents dephosphorylation of B6 forms? |
Binding to proteins in circulation |
|
Involved in A.A. metab and formation of Schiff base |
PLP |
|
Formation of double bond between N and C |
Schiff base |
|
All forms of B6 are metabolized to this form |
PLP |
|
Transfers of an amino group from one A.A. to an alpha-keto acid |
Transamination |
|
Removal of amino group |
Deamination |
|
Common end product of deamination |
ammonia |
|
Removal of carboxyl group from A.A. or molecule, important for neurotransmitter syn |
Decarboxylation |
|
Last vitamin discovered and first natural compound containing cobalt |
Colbalamin/B12 |
|
Vit 12 is not produced by plants or animals it is produced by |
bacteria |
|
Cobalamin is the generic term for group of compounds with corrin nucleus called |
corrinoids |
|
Only two forms active as B12 coenzymes |
Adenosylcobalamin Methylcobalamin |
|
True or false: B12 absorption does not require digestion for absorption |
False |
|
_____ & ___ release cobalamins from polypeptides in the stomach |
Pepsin and HCL |
|
Found in saliva and gastric juice, binds to vitamin and protect from bacterial use |
R Proteins |
|
B12 is excreted in |
Bile |
|
B12- __ complex is needed to be absorbed in the SI by the ileum |
IF |
|
B12-IF binds to a ____ not a transporter at physiological doses |
Receptor |
|
High doses of B12 are absorbed by |
Passive diffusion |
|
B12-IF complex enter the cell via |
Receptor mediated endocytosis |
|
Protein receptor also known as IF receptor or cubam |
Cubillins |
|
Circulating storage form transcobalamin |
TCI |
|
Carries newly absorbed cobalamin to tissues |
TCII |
|
Delivery from peripheral tissues to liver |
TCIII |
|
Main storage form in tissues of B12 |
Adenosylcobalamine |
|
Main storage form of B12 in blood |
Methycobalamine |