Vitamin B6

Question 1

What are the three vitamers of Vitamin B6?

Answer 1

Pyridoxine, pyridoxal, pyridoxamine,

Question 2

What is the chemical structure base of Vitamin B6 compounds?

Answer 2

Pyridine derivatives

Question 3

How do the three forms of B6 differ?

Answer 3

By the functional group at carbon 4 of the pyridine ring

Question 4

What is the functional group in pyridoxine?

Answer 4

Primary alcohol

Question 5

What is the functional group in pyridoxal?

Answer 5

Aldehyde

Question 6

What is the functional group in pyridoxamine?

Answer 6

Amine

Question 7

Where is pyridoxamine mostly found?

Answer 7

In plants

Question 8

Where are pyridoxal and pyridoxamine found?

Answer 8

In animal foods

Question 9

Can pyridoxine be converted to other B6 forms?

Answer 9

Yes

Question 10

Can pyridoxal and pyridoxamine form pyridoxine?

Answer 10

No

Question 11

What is the active coenzyme form of Vitamin B6?

Answer 11

Pyridoxal phosphate (PLP)

Question 12

How is PLP synthesized?

Answer 12

From pyridoxine, pyridoxal, and pyridoxamine

Question 13

How is Vitamin B6 excreted?

Answer 13

As 4-pyridoxic acid in urine

Question 14

What is PLP attached to in enzymes?

Answer 14

Epsilon-amino group of lysine

Question 15

What metabolism is PLP associated with?

Answer 15

Amino acid metabolism

Question 16

Which specialized products depend on pyridoxine?

Answer 16

Serotonin

Question 17

Which reactions involve PLP?

Answer 17

Transamination, decarboxylation, deamination, transsulfuration, condensation

Question 18

What is transamination?

Answer 18

Conversion of amino acids to keto acids

Question 19

What enzyme carries out transamination?

Answer 19

Transaminase

Question 20

Where do keto acids go after transamination?

Answer 20

Citric acid cycle

Question 21

What kind of vitamin is B6 based on its role in energy?

Answer 21

Energy-releasing vitamin

Question 22

What does B6 integrate metabolically?

Answer 22

Carbohydrate and amino acid metabolism

Question 23

What is formed when PLP interacts with amino acids?

Answer 23

Schiff base

Question 24

What is the result of PLP taking the amino group?

Answer 24

Pyridoxamine phosphate

Question 25

Which inhibitory neurotransmitter synthesis depends on PLP?

Answer 25

GABA

Question 26

Is GABA excitatory or inhibitory?

Answer 26

Inhibitory

Question 27

What amino acid is the precursor to catecholamines?

Answer 27

Tyrosine

Question 28

Which catecholamines require PLP for synthesis?

Answer 28

Dopamine, epinephrine and norepinephrine

Question 29

What is PLPís role in heme synthesis?

Answer 29

Required for ?-aminolevulinic acid synthesis

Question 30

What coenzymes are made from tryptophan using PLP?

Answer 30

NAD+ and NADP+

Question 31

Which enzyme needs PLP in niacin synthesis?

Answer 31

Kynureninase

Question 32

What is excreted more in B6 deficiency?

Answer 32

Xanthurenic acid

Question 33

What amino acids does PLP help metabolize?

Answer 33

Sulfur-containing amino acids

Question 34

What enzyme transfers sulfur in cysteine synthesis?

Answer 34

Cystathionine synthase

Question 35

What is taurine?

Answer 35

PLP-dependent decarboxylated product of cysteine, involved in the conjugation bile acids

Question 36

What does taurine help with?

Answer 36

Bile acid conjugation

Question 37

What amino acids require PLP for deamination?

Answer 37

Hydroxyl group-containing amino acids

Question 38

Which enzyme synthesizes serine from glycine?

Answer 38

Hydroxymethyltransferase

Question 39

What does PLP help absorb in the intestine?

Answer 39

Amino acids

Question 40

What condition does B6 prevent in the kidneys?

Answer 40

Hyperoxaluria and stone formation

Question 41

Which animal foods are rich in B6?

Answer 41

Egg yolk, fish, milk, meat

Question 42

Which plant foods are good sources of B6?

Answer 42

Wheat, corn, cabbage, roots and tubers

Question 43

What symptoms are linked to B6 deficiency?

Answer 43

Depression, irritability, nervousness, mental confusion

Question 44

What are severe symptoms of B6 deficiency?

Answer 44

Convulsions and peripheral neuropathy

Question 45

What neurotransmitters are reduced in B6 deficiency?

Answer 45

Serotonin, GABA, epinephrine and norepinephrine

Question 46

What does B6 deficiency cause in children?

Answer 46

Convulsions (epilepsy)

Question 47

What type of anemia is seen in B6 deficiency?

Answer 47

Hypochromic microcytic anemia

Question 48

What is a test indicator for B6 deficiency?

Answer 48

High xanthurenic acid in urine after tryptophan load

Question 49

Who is most at risk for dietary B6 deficiency?

Answer 49

Women on oral contraceptives, alchoholics and infants

Question 50

What drug used for TB causes B6 deficiency?

Answer 50

Isoniazid (INH)

Question 51

What inactive compound does isoniazid form with PLP?

Answer 51

Hydrazone derivative

Question 52

What drug used in Wilson's disease interacts with PLP?

Answer 52

Penicillamine

Question 53

What must be supplemented with isoniazid or penicillamine?

Answer 53

Pyridoxine

Question 54

What are Vitamin B6 antagonists?

Answer 54

Isoniazid, deoxypyridoxine

Question 55

What is a toxic effect of high B6 dose in women of premenstrual syndrome

Answer 55

Sensory neuropathy

Question 56

What dose of B6 may cause neurological damage?

Answer 56

More than 200 mg/day