Cofactors

Question 1

Aminotransferases (AST, ALT)

Answer 1

Used in the urea cycle and for aminotransport

Require B6

Question 2

Alpha-ketoglutarate

Answer 2

TCA cycle

B1, B2, B3, B5, lipoic acid

Question 3

Lactate Dehydrogenase

Answer 3

B3

Used in anaerobic cycle (major pathway in RBC, WBC, kidney medulla, and lens, testes, cornea)

Question 4

Pyruvate Dehydrogenase

Answer 4

B1, B2, B3, B5, lipoic acid

arsenic inhibits lipoic acid: results in vomiting, garlic breath, and diarrhea

Question 5

Pyruvate Carboxylase

Answer 5

Require Biotin (B7)

Question 6

Phosphoenolpyruvate Carboxykinase

Answer 6

Requires GTP

Oxaloacetate –> PEP

Question 7

Transketolase

Answer 7

B1
Ribulose 5 Phosphate –> Ribose 5 phosphate (Nucleotide synthesis) Glucose-3-Phosphate (glycolytic) Fructose 6 Phosphate (glycolytic)

Question 8

Phenylalanine Hydrolase

Answer 8

BH4

phenylalaine –> tyrosine

Question 9

Tyrosine Hydroxylase

Answer 9

BH4

Tyrosine –> Dopa

Question 10

DOPA decarboxylase

Answer 10

B6

DOPA–> dopamine

Question 11

Dopamine Hydroxylase

Answer 11

Vitamin C

Dopamine –> NOREPI

Question 12

Phenylenthanolamine-N-Methyltransferase

Answer 12

SAM

Norepi–> epi

Question 13

Alpha Ketoacid Dehydrogenase

Answer 13

B1 cofactor

Used in the degradation of the branched chain aa following deamination by transaminases

Question 14

Homocysteine Methyltransferase (Methionine Synthetase)

Answer 14

B12, and THF

Homocysteine –> methionine

Question 15

Cystathione Synthase

Answer 15

B6 and serine

Homocysteine –> cystathione

Question 16

Glycogen Phosphorylase

Answer 16

B6

Liberates glucose 1 phosphate residues from glycogen

Question 17

Thymidylate Synthase

Answer 17

requires THF

dUMP–> dTMP

Question 18

ALA synthase

Answer 18

B6
Combines succinyl CoA and glycine –> ALA
* heme synthesis

Question 19

Gaba synthesis

Answer 19

B6