Water Soluble Vitamins

Front 1

What are the enzymatic cofactors?

Back 1

1. Thiamin
2. Pyroxdial
3. Mangenese
4. Robiflavin
5. Pantothenic acid
6. Magnesium
7. Niacin
8. Lipoic Acid
9. Zinc
10. Biotin
11. Vitamin K
12. Copper

Front 2

What two cofactors are needed for electron transfer?

Back 2

niacin and riboflavin

Front 3

what cofactor is needed for transaminations?

Back 3

b6

Front 4

What cofactor is needed for acod/aldehyde tranfers?

Back 4

thaimin

Front 5

What cofactor is needed for Thio-ester transfers?

Back 5

Pantothenic acid- part of coenzyme A

Front 6

What cofactor is needed for decarboxylations?

Back 6

lipoic acid, b6, thiamin

Front 7

What cofactor is needed for carboxylations?

Back 7

biotin

Front 8

What cofactor is needed for one-carbon transfers?

Back 8

b12 and folate

Front 9

what micronutrients are used for one-carbon usage?

Back 9

b12, folate, cobalt

Front 10

What are the antioxidants?

Back 10

Vit E & C, B-carotene, selenium copper

Front 11

What are the micronutrients that are hormones?

Back 11

Vit A & D, iodine for thyroid hormone

Front 12

What are the micronutrients that are used bone formation?

Back 12

calcium, phosphate, magnesium, Vit D, Fluoride

Front 13

What are the micronutrients that are used in vascular homeostasis?

Back 13

sodium, potassium, chloride

Front 14

What are the micronutrients that for cardiovascular function?

Back 14

antioxidants, iron, chromium, magnesium, silicon

Front 15

Thiamin is what vitamin?

Back 15

B1

Front 16

What is vitamin used as a cofactor for?

Back 16

1. Transfer of carboxyl and aldehyde groups in CHO and branched chained amino acid metabolism- decarboxylation & transketolation

2. Neurotransmission and nerve conduction

Front 17

What two enzymes does thiamin help to decarboxylate?

Back 17

1. Pyruvate DH
2. Alpha KG DH

Front 18

What is transketolation? And how is thiamin involved?

Back 18

It is the transfer of aldehyde b/n sugars in the pentose phosphate pathway

Front 19

what is thiamin's role in neurotransmission and nerve conduction?

Back 19

Thiamin affects the level of neurotransmittors (acetylcholine, catecholamines, norepinephren, serotonin) and it's effects are independent of coenzyme function

Front 20

Does TPP accept or donate electrons?

Back 20

BOTH

Front 21

What is the active thiamin metabolite?

Back 21

TPP, TDP- thiamin pyrophosphate

Front 22

where is thiamin pyrophosphate made in the body?

Back 22

made in the liver/brain by thiamin pyrophosphokinase

thiamin+ ATP-> Thiamin-P-P + AMP

Front 23

what does the enzyme TPP-ATP phosphoryl transferase do?

Back 23

TPP->TTP

Front 24

what does the enzyme thiamin pyrophosphatase?

Back 24

TPP-> TMP

Front 25

What is the organ distribution of thiamin?

Back 25

Low in Brain (high fat, lower water in the brain)

High in skeletal muscle (50%), heart, liver, kidney

Front 26

What is the intracellular distribution of thiamin?

Back 26

Nuclear, Mitos (significant amount), cytosol

Mitos- energy metabolism (pyruvate DH and alpha KGDH

Front 27

What are the three TPP-mediated reactions?

Back 27

1. Pentose Phosphate pathway
2. Pyruvate DH
3. Alpha KG DH

Front 28

What is the characteristics of dry beri-beri?

Back 28

Paralytic or nervous beri-beri (thiamin deficiency)

Peripheral neuropathy, memory loss, tingling, numbness, weakness

Front 29

What is the characteristics of wet beri-beri?

Back 29

Cardiovascular problems: enlarged heart, edema, condition worsened by exercise, high CHO diet (stress TCA cycle and glycolysis)

Front 30

What are the characteristics of cerebral beri-beri?

Back 30

Wernicke-korsakoffs syndrome:encephalopathy

occurs in alcoholics- low intake of water-soluble and impaired of intestinal absorption

malnutrition, POW(high milled rice and low meat diet)

confusion, amnesia, cause of dementia

Front 31

What is the characteristics of marginal deficiency of Vitamin B1?

Back 31

A subclinical deficiency is common in the US (17-20%) which means they have a <70% of the RDA

Front 32

Who is at risk for the thiamin deficiency?

Back 32

elderly, children, teens, stress, alcoholics, athletes

Front 33

when is thiamin deficiency diagnosed?

Back 33

autopsy

Front 34

What are the thermolabile antagonists for thiamin?

Back 34

These compounds are destroyed by heat and are thaiminases I and II that degrade thiamin. They are abundant in raw fish and shellfish (sushi?), cabbage, brussel sprouts and microbs

Front 35

What are the thermostable thiamin antagonists?

Back 35

These compounds cannot be destroyed by heat. They are tannins, caffeic acid (tea, cofffee). These tannins and polyphenolics bind and activate thiamin. Calcium and magnesium increase precipitation of thiamin by tannin and make it less bioavailable.

Front 36

What do ruminants have to do with thiamin deficiency?

Back 36

Thiaminase activity of bacteria and some ruminant bacteria can also supply bacteria

Front 37

What are the two analogs that can induce thiamin deficiency?

Back 37

1. oxythiamin chloride: add PP (pyrophosphate) to it and competes with TPP

2. Pyrithiamin: prevents the formation TPP

Front 38

What is leigh's syndrome?

Back 38

is related to thiamin and it is a subacute neuron problem- TTP may enhance brain viability

Front 39

Thiamin-responsive megaloblastic anemia is the mechanism known?

Back 39

unknown mech

Front 40

What is thiamin-responsive lactic acidosis?

Back 40

increase pyr DH activity and removes lactate

Front 41

what is maple syrup urine disease?

Back 41

defective debranching chain ketoacid DH

Front 42

What is the requirement for thiamin?

Back 42

.5 mg/ 1000 kcal
.8 mg/ 1000 kcal- preggy or lactation
1.0 mg /1000 kcal- eldery

Front 43

what are the good dietary sources of thiamin?

Back 43

yeast, lean pork, legumes, grains, pastas, rice are rich sources

Front 44

what are poor dietary sources of thiamin?

Back 44

milk products, seafoods, fruits and vegetables

Front 45

what are some other ways to destroy thiamin?

Back 45

Thiamin is unstable above pH 8 (like if you add sodium barcarbonate), it is destroyed by heat, cooking water, and radiation

NOT by freezing

Front 46

What is the absorption route of thiamin?

Back 46

It is actively abs in the jejunum and ileum (<2um) and its passively diffusion if smaller than 2um

Front 47

what 4 things will decreased thiamin abs?

Back 47

impaired intestinal fxn:
1. alcoholism
2. diarrhea
3. PEM
4. Folate deficiency

Front 48

Transport of thiamin?

Back 48

portal vien-> liver and TPP is bound to protein in the plasma. there is facilitated diffusion into RBC and active transport into other cells.

Front 49

Where is thiamin excreted?

Back 49

urine in the free thiamin form

Front 50

What are the assessment methods for thiamin?

Back 50

1. dietary/medical/family history
2. physical examination
3. lab tets

Front 51

what lab tests are used to assess thiamin?

Back 51

1. urinary thiamin excretion
2. blood thiamin level
3. thiamin in CSF
4. bllod pyruvate, lactate and alpha KG levels
5. erythrocyte thansketolase (ETKA) activity on TPP effect on ETKA

Front 52

Are the measurements to assess thiamin direct or indirect?

Back 52

indirect

Front 53

what are the downsides to using the erythrocyte transketolase activity for thiamin status?

Back 53

tissue thiamin can lose up to 50% of stores before this enzyme starts to decrease in levels, aka show deficiency and the recovery time is slow also. the thaimin levels in teh body can be increased but the enzyme won't be increased

Front 54

if we use thiamin analogs what happens in cells?

Back 54

cells take up the analogs not thiamin

Front 55

is thiamin assessment tissue specific?

Back 55

yes, there's a large variance between the amounts of thiamin in certian tissues. for example the brain always has a constant level (buffer) but the spleen is greatly effected by little changes

Front 56

is thiamin assessment greater as the deficiency progresses?

Back 56

yes, the TPP stimulation is greater as the deficiency progresses. the levels of stimulation depends of the level of deficiency

Front 57

what is the toxicity for B1?

Back 57

only at 1000x the RDA

Front 58

What forms of riboflavin are there?

Back 58

1. riboflavin which is the abs form
2. FMN- flavin mononucleotide which is riboflavin + P
3. FAD- flavin adenine dinucleotide= ribflavin + ADP

Front 59

what two forms of riboflavin are cofactors?

Back 59

FMN and FAD

Front 60

what two enzymes make FMN and FAD?

Back 60

1. flavokinase makes FMN by = this rxn riboflavin + ATP -> FMN + ADP

falvokinase expression is enhanced by the thyroid hormone and aldosterone

2. FAD synthetase: FMN + ATP-> FAD + ppi

FAD synthetase has feedback inhibition by FAD

Front 61

FMN/FAD have what common characteristics?

Back 61

1. they are cofactors for oxidation/reduction reactions
2. they are donors and acceptors of two protons
3. they are essential in beta- oxidation and the TCA cycle

ex. succinate DH: succinate + FAD ->fumarate + FADH2

fatty acid oxidation:
palmitate + FAD-> palmitic + FADH2

Front 62

is ariboflavinosis common with other nutrient deficiencies?

Back 62

yes

Front 63

symptoms of riboflavin deficiency

Back 63

-cheilosis
-glossitis
-growth cessation
- cornea vascularization
-skin lesion because a B2 def leads to impaired B6 conversion to its coenzyme which leads maturation of collagen synthesis
-impaired conversion of tryptophan to niacin

Front 64

what are some predisposing conditions that can lead to riboflavin deficiency?

Back 64

-lactose intolerance
-kidney dialysis (removes B2)
-hyperthyriodism:drugs suppress flavokinase
-oral contraceptives: high estrogen and depletes circulation riboflavin
-alcoholism
-malabsorption
-chronic stress

Front 65

what are the two therapeutic things riboflavin is used for?

Back 65

1. carpal tunnel syndrome: alleviated with B6 and B2 is helpful with B6 activation

2. inborn errors of metabolism: those involving FAD-dependent enzymes and B2 administration is helpful

Front 66

what is the absorption of riboflavin?

Back 66

gastric acid releases coenzymes (FAD & FMN) from noncovalent attachment to proteins- pyrophosphatase and phosphatase free riboflavin from FAD/FMN and there is active transport at low conc (Na/K ATPase dep.)

Front 67

how is it riboflavin transported?

Back 67

it is transported as riboflavin with binding protein (85%) and albumin (13-15%)

Front 68

riboflavin cellular absorption

Back 68

it enhanced thyroid, facilitated diffusion at physiological levels and simple diffusion at higher levels

Front 69

is there riboflavin toxicity?

Back 69

no

Front 70

sources of thiamin

Back 70

eggs, meats, dairy, broccoli, enriched grain products

it is responsible for yellow color of yolk

Front 71

requirement of thiamin

Back 71

1. 0.6 mg/1000 kcal for all ages
2. 1.2 mg/day for intake <2000 kcal
3. Addition 0.3 mg/day for pregnant women
4. Additional 0.4-0.5 mg/day for lactating women

Front 72

how do you assess the riboflavin?

Back 72

Activity coefficient (AC): red cell glutathione reductase in presence/absence of exgenous

acceptable level: <1.2
Low: 1.2-1.4
Deficient: >1.4

Front 73

What are the forms of niacin?

Back 73

1. Niacin-absorption form (nicotinic acid)
2. Nicotinamide- circulating form
3. NAD, NADP- active cofactor form

Front 74

what does the active form of the niacin do in the body?

Back 74

-electron carrier in oxidation/reduction rxns
1. DH
2. ATP production
3. reducing agent

Front 75

what are characteristics NAD/NADH?

Back 75

-ATP syn: catabolic
1. glycolysis
2. pyruvate DH
3. TCA cycle oxidation
4. fatty acid oxidation
5. ethanol oxidation

Front 76

what are the characteristics of NADP/NADPH?

Back 76

(maintenance & growth: anabolic)
1. fatty acid synthesis
2. cholesterol/steroid syn
3. glutamate DH
4. dNTP synthesis
5. pyr/malate shuttle

Front 77

what is pellagra and its conditions?

Back 77

its a niacin deficiency. its signs are weakness, indigestion, lack of appetite, and it progresses to 3 D's: dermatitis, diarrhea, dementia.

Front 78

what cures pellagra?

Back 78

50-250 mg/day

Front 79

what are the predisposition to pellagra?

Back 79

1. a corn based diet: that is high in leu (imbalanced of EAAs), leu competes for Trp transporter transporter, and leu blocks the synthesis of NAD (bc can be syn by AA Trp)

2. deficiencies of B6, Cu, B2 which are involved in trp -> niacin

Front 80

synthesis of trp- characteristics?

Back 80

- the conversation: 1/60
ex 60g of protein = 600 mg trp =10mg niacin

and the first step (oxidase) enhanced 3x by oral contraceptives and pregnancy

Front 81

what are the therapeutic uses of niacin?

Back 81

1. hyperlipidemia: 1.5-6 g of niacin (1000x- high levels)
- lowers serum chol and TAG
-average drop is 10-15%
-mechanism uncertain:may interact with membrane receptor, adenylate cyclase, inhibit adipocyte lipolysis thru G protein that inhibits sensitive lipase or decr VLDL syn and secretion in liver

2. CA- help with DNA repair

Front 82

what are the side effects of the therapeutic doses of niacin?

Back 82

1. flushing of neck and face
2. itching
3. histamine release

Front 83

what are the side effects of niacin therapeutic doses partly blocked by?

Back 83

cyclooxygenase inhibitors (aspirin) given 30 min before niacin

Front 84

what is the requirement of niacin?

Back 84

adult: 6.6 mg/1000 kcal
infant: 5-6 mg daily

Front 85

sources of niacin

Back 85

meat, liver, legumes, milk, eggs, fish, grain products

Front 86

how do you assess niacin status?

Back 86

1. urinary metabolites : N1-methyl-nicotinamide and you are deficient <0.8 mg/day

2.NAD(H)/NADP(H) ratio: ratio>1 adequacy ratio<1 deficiency

Front 87

what makes up phosphopantetheine?

Back 87

b-mercaptonethylamine + pantothenic acid + phosphate

Front 88

what makes up coenzyme A?

Back 88

b-mercaptonethylamine + pantothenic acid + phosphate + AMP

Front 89

what is pantothenic acid used for?

Back 89

the reaction of coenzyme A and forms high energy thio-ester bonds with carboxylic acids, carriers acyl groups in degradation/synthesis reactions

Front 90

pantothenic acid is used in over 70 metabolic rxns name some

Back 90

1. high energy bond transfer in glycolysis/ krebs
2. fatty acid oxidation and synthesis
3. steriod/cholesterol synthesis
4. protein modications with fatty acids and isoprenoids
5. acetylcholine, sphingosine synthesis

ex pyr DH, citrate synthase

Front 91

deficiency of pantothenic acid- is it rare? what are the risk factors?

Back 91

extremely rare

risk factors: chronic malnutritoin, alcoholism, disruption of GI fxn

Front 92

what are the symptoms of B5 deficiency?

Back 92

vomiting, weakness, insomnia, immune impairement, abdominal distress, leg cramps, fatigue, burning cramps, tender heels, growth failure

Front 93

Protein Modification: with pantothenic acid-acetylation examples

Back 93

1. need acetylation on the thr, ser, met and sometimes acidic and lysine residues, cytochrome C, actin, histones, DNA-binding proteins: around ~80% of soluble proteins are acetylated at N-terminus

Front 94

what is purpose of acetylation?

Back 94

protects from ubiquitination-dependent protein degradation and is required for assembly and stability of 3D protein structures

Front 95

what is ubinquitination?

Back 95

a small peptide linked to N-terminus to signal degradation

Front 96

what is myristolation?

Back 96

add a Fatty acid protein at the NH2 terminal glycine residue thru amide bond which is irreversible

Front 97

some examples of proteins that are myristolated

Back 97

cAMP protein kinase, src

Front 98

what is the purpose of myristolation?

Back 98

to protect from ubiqutination and help attach the protein to cell membrane

it is also required for exit from the golgi apparatus