Term
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Definition
Vitamin B1
assists in the cleavage of bonds adjacent to a carbonyl group (acetaldehyde transfer)
key to the utilization of met carbon sources as energy (CAC -acetylCoA)
precursors of enzyme cofactors and nucleic acids (PPP) |
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Term
| Thiamine unique chemistry |
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Definition
C-2 of Thiazolium ring is the site of attachment of the "active acetaldehyde" group
and attacking nucleophile that assists in the decarboxylation reactions
has resonance stabilization which creates an electron sink** |
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Term
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Definition
| when a structure prevents the reactivity of another group from compromising the reaction with side groups |
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Term
Pyruvate dehydrogenase+ alpha ketoglutarate dehydrogenase
dependent on TPP |
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Definition
1. pyruvate dehydrogenase enzyme complex depends on Thiamine pyrophosphate to decarboxylate pyruvate on E1 and transfers acetaldehyde to E2
alpha ketoglutarate dehydrogenase has similar complex converting alpha-ketoglutarate to succinyl-CoA |
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Term
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Definition
deficiency in Vitamin B1
paralysis and atrophy of limbs, cardiac failure
neurological symptoms |
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Term
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Definition
| whole grains, yeast, liver |
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Term
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Definition
Vitamin B6
all aminotransferases use PLP as a prosthetic group
exhibits ping-pong kinetics
important in amino acid catabolism, CAC intermediates
sequesters toxic ammonia as glutamine |
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Term
| Pyridoxine unique chemistry |
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Definition
electron sink on pyridinium ring which delocalizes a negative charge
Schiff base* resonance of intermediates |
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Term
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Definition
rare
dermatitis and glossitis
occurs in elderly and diets with severe nut. deficincies |
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Term
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Definition
| meats, whole grain, vegetables, nuts |
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Term
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Definition
Vitamin B2- (FAD)
in electron transfer 1 or 2 e
in oxidative phosphorylation (CAC, E transport, FA oxid) |
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Term
| Riboflavin unique chemistry |
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Definition
redox
the standard reduction potential at which they operate is dependent upon the nature of their interaction with their carrier enzyme |
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Term
| Good Sources of Vitamin B2 |
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Definition
| asparagus, bananas, okra, chard, cottage cheese, milk, yogurt |
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Term
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Definition
rare
due to high affinity of flavoproteins for flavins |
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Term
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Definition
Vitamin B3 - NAD
2 electron transfers only
freely diffusible (redox pot doesn't vary)
CAC, E tra, aa oxi, glycolysis, FA oxi |
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Term
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Definition
NAD+ is for catabolic reactions
NADPH is for anabolic reactions
dehydrogenases use common motif "Rossmann fold" to bind NAD |
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Term
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Definition
Pellagra
causes diarrhea, dementia, dermatitis |
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Term
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Definition
| meat, wheat germ, dairy products and yeast |
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Term
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Definition
Vitamin C
reducing agent
is an antioxidant that keeps the non-heme iron of prolyl-4-hydoxylase in its reduced form
iron remains oxidized and proline hydroxylation activity is abolished
pathway - collagen synthesis |
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Term
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Definition
alpha2,beta2 tetramer
essential for collagen stability
alpha contains 1 non-heme iron
can also decarboxylate alpha-ketoglutarate in an uncouple reaction
if Fe2+ remains oxidized after this reaction due to lack of ascorbic acid, enzyme inactive and can't hydroxylate proline
this leads to connective tissue problems |
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Term
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Definition
scurvy
connective tissue problems
tooth loss |
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Term
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Definition
involves the transfer of one-carbon fragments from one molecule to another
essential for the synthesis of nucleotides, aa and regulation of bio processes |
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Term
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Definition
Vitamin B7
1C metabolism
coenzyme, serves as a carrier of active CO2
CAC, gluconeogenesis (pyurvate carboxylase) |
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Term
| Good Dietary Sources of B7 |
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Definition
| swiss, chard, tomatoes, romaine lettuce, carrots |
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Term
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Definition
Vitamin B12
1C metabolism
cofactor in enzymes where a substituted alkyl group is exchanged for a hydrogen on an adjacent C, w/o H20 accessing the H atom
FA oxid in od #, methionine synthesis |
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Term
| Avidin or streptavidin pull-down assay |
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Definition
Avidin immobilized onto solid supports is also used as purification media to capture biotin labled proteins
used in western blot, ELISA |
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Term
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Definition
CAC deficient in oxaloacetate use BIOTIN
pyruvate to oxaloacetate
allows citrate synthase to use more acetyl-CoA
pyruvate carboxylase requires acetyl-CoA for activity |
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Term
| Vitamin B12 unique chemistry |
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Definition
carbon-cobalt bonds allows reversible free radical generation
only 2 b12 containing enzymes
-methylmalonyl-CoA mutase
-methionine synthase |
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Term
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Definition
Leads to pernicious anemia
reduced production of rbc, reduced levels of hemoglobin, progressive CNS impairment |
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Term
| Good sources of Vitamin B12 |
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Definition
| fish, meat, poultry, eggs, milk |
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Term
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Definition
Vitamin B9 (THF - tetrahydrofolate)
acts as a carrier of 1C units in a variety of metabolic reactions |
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Term
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Definition
not readily converted to the other forms of folate
bioavialbility is limited causing methyl-folate trap |
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Term
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Definition
Methionine synthase reaction requires B12 = ALL FOLATE must go through reaction
it is the only way to convert N5 methyl-THF to a convient form
B12 deficiency will lead to a build up of N5-methyl-THF leading to a shortage of other forms of folate and subsequent impairment in other processes |
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Term
| uses of 1C framgents on THF |
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Definition
purine biosynthesis - N10-formyl-THF
Thymidylate synthase - N5, N10 methylen
Methionine Synthasis - N5- methyl-THF |
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Term
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Definition
are analogues of p-aminobenzoic acid and inhibit dihydropteroate synthetase
which is a bacterial enzyme that synthesizes folic acid
these compounds inhibit bacterial folate synthesis are excellent antibiotics, mamals are dependent on dietary folate |
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Term
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Definition
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Term
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Definition
megaloblastic anemia
cant make thymidylate and purines required for growth
impaired methylation |
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Term
| Homocystein as diagnostic target |
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Definition
| in the blood mirrors the efficiency of 1C metabolism as a diagnostic target of a variety of disorders associated with impaired methylation |
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Term
| Homocystein unique chemistry |
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Definition
reactive free thiol group
it can spontaneously form adducts with a # of important macromolecules in particular proteins
can potentially disrupt solvent-accessible disulfide bonds |
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Term
| Negative concequeneces of impaired methylation |
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Definition
global hypomethylation and localized hypomethylation of DNA
impaire regulation of important genes
implicated in vascular disease and cancer
high homocystein will inhibit methylation reactions involving SAM |
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