Amino acid metabolism

Question 1

What are the 3 destinations for amino acids?

Answer 1

Protein synthesis
Direct use/minor modification
Breakdown and redeployment

Question 2

What neurotransmitter is made up of arginine?

Answer 2

NO

Question 3

What neurotransmitter is made up of Tryptophan?

Answer 3

Serotonin

Question 4

What neurotransmitters are made up of Tyrosine?

Answer 4

Dopamine
Noradrenaline
Adrenaline

Question 5

What neurotransmitter is made up of Glutamate?

Answer 5

GABA

Question 6

Which amino acid makes thyroxine hormone?

Answer 6

Tyrosine

Question 7

WHich amino acid makes Melatonin hormone?

Answer 7

Tryptophan

Question 8

How is the amino acid molecule broken down and what is the role of the products?

Answer 8

NH3-> Ammonia which is TOXIC

Carbon skeleton-> Co2+H2O in energy production
Biosynthetic pathways

Question 9

How are amino acids converted to urea?

Answer 9

AA transaminated to form Alpha-ketoglutarate then glutamate then ammonia then urea

Question 10

What are the enzymes used in transamination?

Answer 10

Aminotransferases

Question 11

What is produced in transamination and which enzymes are used?

Answer 11

Aminotransferase
Produces Alpha Keto-acids

With Alpha-Ketoglutarate -> glutamate

Question 12

What prosthetic group do aminotransferases use to do the amino acid transfer?

Answer 12

Vit B6-derived ‘Pyridoxal Phosphate’ PLP

Question 13

Describe deamination

State the equation.

Answer 13

Glutamate + H20 -> Alpha-ketoglutarate and NH4+

With NAD+->NADH via Glutamate Dehydrogenase

Question 14

What inhibits and activates the deamination reaction?

Answer 14

Inhibited by GTP

Activated by ADP

Question 15

State the equation for urea synthesis

Answer 15

Co2 + NH4+ + H2O + 2ATP -> Carbamoyl Phosphate + 2 ADP + Pi

W/ carbamoyl phosphate synthetase

Question 16

Where does deamination and urea synthesis occur?

Answer 16

In the mitochondrion

Question 17

Describe the urea cycle

Answer 17

Ar -> Ornithine -> Citrulline -> Argino-succinate#

enzymes are Arginase-> Ornithine carmoyl transferase -> Arinion Succinate synthetase-> Arginino succinate lyase

Question 18

What is the structure of urea?

Answer 18

NH2 C=0 NH2

Question 19

What is the overall energy cost to make one molecule of urea?

Answer 19

4 ATP

Question 20

What is extrahepatic tissue?

An what can it do?

Answer 20

Tissue outside the liver
Catabolises Amino Acid to NH3 but can’t make urea

so in the kidney Gln deaminated back to GLu to release NH3 into urine

Question 21

What 7 molecules could the carbon skeleton end up as?

Answer 21

Pyruvate
Acetyl CoA
Acetoacetyl CoA
Alpha-ketoglutarate
Succinyl CoA
Fumarate
Oxaloacetate

Question 22

Which amino acids make Alpha-ketoglutarate?

Answer 22

Arginine
Glutamate
Glutamine
Histidine
Proline

Question 23

Which amino acids make Succinyl CoA?

Answer 23

Isoleucine
Methionine
Threonine
Valine

Question 24

Which amino acids make fumarate?

Answer 24

Aspartate
Phenylalanine
Tyrosine

Question 25

Which amino acids make Oxaloacetate?

Answer 25

Asparagine

Aspartate

Question 26

Which amino acids make Pyruvate?

Answer 26

Alanine
Cysteine
Glycine
Serine
Threonine
Tytophan

Question 27

Which amino acids make Acetyl CoA?

Answer 27

Isoleucine
Leucine
Tryptophan

Question 28

Which amino acids make Acetoacetyl CoA?

Answer 28

Leucine
Lysine
Phenylalanine
Tryptophan
Tyrosine

Question 29

How is Sulphur disposed of?

Answer 29

Removed as cysteine then (oxidised )Transamination then to produce H2S or So2 or So42’

Question 30

Name the essential amino acids.

Answer 30

Phenylalanine 
Histidine
Isoleucine
Lysine
Leucine
Methionine
Theronine
Valine
Tryptophan

( FHIKLMTVW)

Question 31

What are pyrimidines synthesized from?

Answer 31

Asp

Carbamoyl Phosphate

Question 32

What are purines made from?

Answer 32

Asp
Gln
Gly