Nutrition

Question 1

Which enzymes/processes use vitamin B1 (thiamin)?

Answer 1

pyruvate dehydrogenase (glycolysis/TCA), alpha-ketoglutarate dehydrogenase (TCA), HMP transketolase (pentose phosphate pathway), branched-chain alpha-ketoacid dehydrogenase complex (BCaKDH, breakdown of Leu, Ile, and Val)

Question 2

Which enzymes/processes use vitamin B2 (riboflavin)?

Answer 2

pyruvate dehydrogenase (glycolysis/TCA), alpha-ketoglutarate dehydrogenase (TCA), glutathione reductase (antioxidant rxns), methylene-tetrahydrofolate reductase (folate cycling), electron transport chain complex I, succinate dehydrogenase (TCA), acyl-CoA dehydrogenase (fatty acid beta oxidation)

Question 3

Which enzyme is the first to exhibit diminished function in vitamin B1 deficiency?

Answer 3

HMP transketolase

Question 4

Which enzyme is the first to exhibit diminished function in vitamin B2 deficiency?

Answer 4

glutathione reductase

Question 5

Which enzymes/processes use vitamin B3 (niacin)?

Answer 5

pyruvate dehydrogenase (glycolysis/TCA), alpha-ketoglutarate dehydrogenase (TCA), 3-phosphoglyceraldehyde dehydrogenase (glycolysis), isocitrate dehydrogenase (TCA cycle), malate dehydrogenase (TCA cycle), beta-ketoacyl-ACP reductase (fatty acid synthesis), enoyl-ACP reductase (fatty acid synthesis), enoyl-ACP reductase (fatty acid synthesis), HMG-CoA reductase (cholesterol synthesis), glucose-6-phosphate dehydrogenase (pentose phosphate pathway), 6-phosphogluconate dehydrogenase (pentose phosphate pathway)

Question 6

Which enzymes/processes use pantathenic acid (CoA-SH)?

Answer 6

pyruvate dehydrogenase (glycolysis/TCA), alpha-ketoglutarate dehydrogenase (TCA)

Question 7

Which enzymes/processes use vitamin B7 (biotin)?

Answer 7

pyruvate carboxylase (gluconeogenesis), acetyl-CoA carboxylase (fatty acid synthesis), proprionyl-CoA carboxylase (branched-chain AA and odd-chain fatty acid catabolism)

Question 8

Which enzymes/processes use vitamin B6 (pyridoxine)?

Answer 8

transamination and decarboxylation of AAs (AA catabolism), non-essential AA synthesis, histidine-histamine, NT synthesis, glycogen phosphorylase (glycogen breakdown)

Question 9

Which enzymes/processes use vitamin B9 (folic acid)?

Answer 9

purine/pyrimidine synthesis (DNA/RNA synthesis), methionine synthetase (methionine/methylation cycle), histidine catabolism

Question 10

Which enzymes/processes use vitamin B12?

Answer 10

methionine synthetase (methionine/methylation cycle), methyl malonyl mutase (branched-chain AA catabolism)

Question 11

Which enzymes/processes use vitamin E?

Answer 11

antioxidant: scavenges free radicals to prevent fatty acid oxidation

Question 12

Which enzymes/processes use vitamin C?

Answer 12

Vitamin E recycling, free radical scavenging, cytochrome B (intestinal Fe reduction and absorption), proline and lysine hydroxylation in collagen synthesis

Question 13

Which enzymes/processes use vitamin A?

Answer 13

transcription factor; retinol: reproduction and spermatogenesis; retinal: vision; retinoic acid: epithelial cell differentiation/maintenance, embryonic development, immune function

Question 14

Which enzyme is the first to exhibit decreased deficiency in vitamin B12 deficiency?

Answer 14

methyl malonyl mutase (BCAA catabolism)

Question 15

What does pyruvate dehydrogenase do, and what vitamins/cofactors does it use?

Answer 15

bridges glycolysis and TCA cycle (converts pyruvate into acetyl-CoA); vitamins B1 (thiamin), B2 (riboflavin), and B3 (niacin), pantothenic acid (CoA-SH)

Question 16

What does alpha-ketoglutarate dehydrogenase do, and what vitamins/cofactors does it use?

Answer 16

part of the TCA cycle (converts alpha-ketogluarate into succinyl-CoA); vitamins B1 (thiamin), B2 (riboflavin), and B3 (niacin), pantothenic acid (CoA-SH)

Question 17

What does HMP transketolase do, and what vitamin does it use?

Answer 17

catalyzes two steps in the pentose phosphate pathway; vitamin B1 (thiamin)

Question 18

What does glutathione reductase do, and what vitamin does it use?

Answer 18

uses NADPH to reduce/recyle glutathione; vitamin B2 (riboflavin)

Question 19

what does branched-chain alpha-ketoacid dehydrogenase do, and what vitamin does it use?

Answer 19

breaks down branched-chain amino acids valine, leucine, and isoleucine (when mutated, causes maple syrup urine disease); vitamin B1 (thiamin)

Question 20

what does methylene tetrahydrofolate reductase do, and what vitamin does it use?

Answer 20

converts methylene-THF into methyl-THF for use in the one-carbon pathway; vitamin B2 (riboflavin)

Question 21

what vitamin does electron transport chain complex I use?

Answer 21

vitamin B2 (riboflavin)

Question 22

what does succinate dehydrogenase do, and what vitamin does it use?

Answer 22

part of the TCA cycle and acts as complex II of the electron transport chain; vitamin B2 (riboflavin)

Question 23

what does acyl-CoA dehydrogenase do, and what vitamin does it use?

Answer 23

part of fatty acid beta-oxidation; vitamin B2 (riboflavin)

Question 24

what does 3-phosphoglyceraldehyde dehydrogenase do, and what vitamin does it use?

Answer 24

glycolysis; vitamin B3 (niacin)

Question 25

what does isocitrate dehydrogenase do, and what vitamin does it use?

Answer 25

TCA cycle; vitamin B3 (niacin)

Question 26

what does malate dehydrogenase do, and what vitamin does it use?

Answer 26

TCA cycle; vitamin B3 (niacin)

Question 27

what does beta-ketoacyl-ACP reductase do, and what vitamin does it use?

Answer 27

fatty acid synthesis; vitamin B3 (niacin)

Question 28

what does enoyl-ACP reductase do, and what vitamin does it use?

Answer 28

fatty acid synthesis; vitamin B3 (niacin)

Question 29

what does HMG-CoA reductase do, and what vitamin does it use?

Answer 29

cholesterol synthesis; vitamin B3 (niacin)

Question 30

what does glucose-6-phosphate dehydrogenase do, and what vitamin does it use?

Answer 30

pentose phosphate pathway; vitamin B3 (niacin)

Question 31

what does 6-phosphogluconate dehydrogenase do, and what vitamin does it use?

Answer 31

pentose phosphate pathway; vitamin B3 (niacin)

Question 32

what does pyruvate carboxylase do, and what vitamin does it use?

Answer 32

gluconeogenesis (converts acetyl-CoA --> oxaloacetic acid); vitamin B7 (biotin)

Question 33

what does acetyl-CoA carboxylase do, and what vitamin does it use?

Answer 33

fatty acid synthesis; vitamin B7 (biotin)

Question 34

what does proprionyl-CoA carboxylase do, and what vitamin does it use?

Answer 34

branched-chain amino acid and odd-chain fatty acid catabolism; vitamin B7 (biotin)

Question 35

what does glycogen phosphorylase do, and what vitamin does it use?

Answer 35

glycogen breakdown; vitamin B6 (pyridoxine)

Question 36

what does methionine synthetase do, and what vitamins does it use?

Answer 36

converts homocysteine --> methionine in the one-carbon cycle; vitamin B9 (folate) and B12

Question 37

what does methyl malonyl mutase, and what vitamin does it use?

Answer 37

branched-chain AA catabolism; vitamin B12

Question 38

what other nutrients does vitamin B6 (pyridoxine) require to be biologically active/useful?

Answer 38

vitamin B2 (riboflavin) and zinc

Question 39

what enzyme is required to make dietary folate biologically active?

Answer 39

glutamate carboxypeptidase (cleaves glutamate moieties)