The "One Carbon Metabolism" B-vitamins (B6, B9, B12)

Question 1

Vitamin B6 is

Answer 1

Pyridoxine

Question 2

The supplement form of B6

Answer 2

Pyridoxine

Question 3

The active cofactor form of B6

Answer 3

Pyridoxal 5’-phosphate (PLP)

Question 4

What are the 5 types (more than 100 individual) PLP-dependent reactions?

Answer 4

Transaminations, Decarboxylations, 1st step in heme synthesis, one-carbon metabolism, lipid and carb metabolism

Question 5

Converstion of amino acids to respective ketoacids

-Ex. Glutamate to α ketoglutarate

Answer 5

Transamination

Question 6

Elimination of CO2

-Ex. L-dopa to dopamine

Answer 6

Decarboxylations

Question 7

The first step of heme synthesis, which requires B6 is

Answer 7

Succinyl CoA + Glycine = δ Aminolevulinate

Question 8

Functions in serine-glycine conversion and homocysteine catabolism

Answer 8

B6

Question 9

Functions in sphingolipid synthesis and in muscle glycogen phosphorylase

Answer 9

B6

Question 10

Which 4 things can be caused by vitamin B6 deficiency?

Answer 10

Microcytic anemia, convulsions and EEG abnormalities, Hyperhomocysteinemia, and inflammatory disease

Question 11

Classified as inhibited heme synthesis

Answer 11

Microcytic anemia

Question 12

Cause by inhibited neurotransmitter synthesis (e.g. serotonin, dopamine) and the accumulation of toxic products of tryptophan metabolism

Answer 12

convulsions and EEG abnormalities in B6 deficiency

Question 13

Vitamin B6 deficiency results in inhibited catabolism of

Answer 13

Homocysteine

Question 14

This hyperhomocysteinemia icreases the risk of

Answer 14

Vascular disease

Question 15

Inflammatory bowel disease and rheumatoid arthritis can be caused by

Answer 15

PLP deficiency

Question 16

As inflammation increases, B6 status

Answer 16

Decreases

Question 17

Vitamin B9 is

Answer 17

Folate/folic acid

Question 18

The synthetic, supplement form of folate

Answer 18

Folic acid

Question 19

How many active forms of folate are there?

Answer 19

6

Question 20

Folate functions predominantly in

Answer 20

One-carbon metabolism

Question 21

What are the three types of one-carbon metabolism that folate function in?

Answer 21

1. ) DNA/RNA synthesis
2. ) Methionine recycling
3. ) S-adenosylmethionine (SAM) synthesis

Question 22

Folate functions to convert homocysteine to

Answer 22

Methionine

Question 23

Folate functions to produce which 3 nucleic acids?

Answer 23

Thymidine, Adeniene, and Guanine

Question 24

What are three common pathologies associated with folate deficiency?

Answer 24

1. ) Macrocytic (megalolastic) anemia
2. ) Hyperhomocysteinemia
3. ) Neural tube defects

Question 25

Which two neural tube defects can be caused by folate deficiency?

Answer 25

Spina bifida and Anencephaly

Question 26

Folic acid reduces

Answer 26

Neonatal Deaths

Question 27

Folic acid has also been show to help in primary prevention of

Answer 27

Stroke

Question 28

Folic acid toxicity may mask

Answer 28

B12 deficiency

Question 29

May promote cancer growth

Answer 29

Folic acid toxicity

Question 30

What is vitamin B12?

Answer 30

Cobalamin

Question 31

The synthetic, supplemental form of Vitamin B12 (cobalamin)

Answer 31

Cyanocobalamin

Question 32

There are 4 different forms of B12, which are characterized by their R groups. What are the 4 types of R groups for vitamin B12?

Answer 32

CN, OH, CH3, and Deoxyadenosyl

Question 33

The CN and OH forms are the

Answer 33

Supplement forms

Question 34

Vitamin B12 requires which three transport proteins for absorption and bioavailability?

Answer 34

1. ) Haptocorrin (HC)
2. ) Intrinsic Facotr (IF)
3. ) Transcobalamin (TC)

Question 35

Found in saliva

Answer 35

HC

Question 36

Produced by the parietal cells of the stomach

Answer 36

IF

Question 37

Found in intestinal cells

Answer 37

TC

Question 38

B12 absorption also requires

Answer 38

Stomach acid (HCl)

Question 39

What are the two main functions of Vitamin B12?

Answer 39

One-carbon metabolism and odd-chain FA metabolism

Question 40

Functions in the same 3 one-carbon metabolism reactions as Folate

Answer 40

B12

Question 41

Functions in the conversion of methylmalonyl CoA to Succinyl CoA in the Krebs cycle

Answer 41

B12

Question 42

What are the three pathologies associated with B12 deficiency?

Answer 42

Macrocytic (megaloblastic) Anemia, Hyperhomocysteinemia, and Neurological diseases

Question 43

Can lead to degeneration of the spinal cord

Answer 43

B12 deficiency

Question 44

B12 deficiency can also lead to the degeneration of nerves in the

Answer 44

Hands and Feet (peripheral neuropathy)

Question 45

Can lead to degeneration of the brain (cognitive impairment and dementia)

Answer 45

B12 deficiency

Question 46

What are the two causes of B12 deficiency?

Answer 46

1. ) Dietary deficiency

2. ) Malabsorption

Question 47

Vegans and vegetarians with low intake of animal source foods are at risk for

Answer 47

B12 deficiency

Question 48

An autoimmune disorder characterized by a loss of IF in the stomach

-B12 deficiency occurs fast and can be fatal

Answer 48

Pernicious anemia

Question 49

The loss of stomach acid which prevents B12 from being absorbed in food

-B12 can be absorbed by pill

Answer 49

Atrophic gastritis

Question 50

In Pernicius anemia, patients can not absorb B12 from

Answer 50

Food or Pills

Question 51

Vitamin B supplementation helps to slow

Answer 51

Brain atrophy