Amino Acid Anabolism

Question 1

List the 10 NONessential amino acids

Answer 1

Ala, Asp, Asn, *Cys, Glu, *Gln, Gly, Pro, Ser, *Tyr

Question 2

List the 10 essential amino acids

Answer 2

PVT TIM HALL

Phe, Val, Trp, Thr, Ile, Met, His, *Arg, Leu, Lys

Question 3

Conditionally essential amino acid: This amino acid is essential for neonates because this pathway is not well developed in newborns

Answer 3

Cysteine

Question 4

Conditionally essential amino acid: This amino acid is essential for PKU patients; require Phe (essential)

Answer 4

Tyrosine

Question 5

Conditionally essential amino acid: This amino acid is required for growing infants and under severe illness

Answer 5

Glutamine

Question 6

Conditionally Essential amino acid: This amino acid is generally considered essential even though it is generated in the urea cycle.

Answer 6

Arginine

Question 7

Describe the synthesis of Glutamate

Answer 7

alpha-ketoglutarate to Glutamate via Glutamate dehydrogenase, transaminases, etc.

Question 8

Describe the synthesis of Glutamine

Answer 8

Glutamate–>Glutamine via Glutamine synthesis

Question 9

Describe the synthesis of Alanine

Answer 9

pyruvate–>Alanine via ALT (Alanine transaminase)

Question 10

Describe the synthesis of Aspartate

Answer 10

OAA–>Asp via AST (Aspartate transaminase)

Question 11

Describe the synthesis of Asparagine

Answer 11

Aspartate–>Asparagine via Asparagine synthetase

Question 12

Describe the synthesis of Tyrosine

Answer 12

Phenylalanine–>Tyrosine via phenylalanine hydroxylase

Question 13

Describe the synthesis of Proline

Answer 13

Glutamate–>Prline via a 3 step pathway (later described)

Question 14

Describe the synthesis of Serine

Answer 14

3-P-glycerate–>Serine via a 3 step pathway (later described)

Question 15

Describe the synthesis of Glycine

Answer 15

Serine–>Glycine via H4 folate in 1-carbon pool

Question 16

Describe the synthesis of Cysteine

Answer 16

Serine–>Cysteine using Methionine as sulfur source

Question 17

1st step of making either Proline or Ornithine from Glutamate

Answer 17

Glutamate–>Glutamate semialdehyde using “uncharacterized enzymes”; ATP–>ADP = Pi, NADH–>NAD+

Question 18

Two fates of Glutamate Semialdehyde

Answer 18

1) Glutamate semialdehyde–>Ornithine via aminotransferase. Ornithine is an intermediate in the urea cycle and can potentially make Arginine.
2) Glutamate semialdehyde–>pyrroline carboxylate (spontaneous rxn)–>Proline via Pyyroline-5-carboxylase reductase

Question 19

How do we get Glutamate from glucose?

Answer 19

When we break down Proline (made from Glutamate), glutamate goes back into alpha-KG and alpha-KG comes from the TCA cycle=GLUCOSE!

Question 20

1st step of Serine synthesis

Answer 20

3-Phosphoglycerate–> 3-Phosphopyruvate via phosphoglycerate dehydrogenase; NAD+–>NADH + H+

Question 21

2nd step of Serine synthesis

Answer 21

3-Phosphopyruvate–>3-Phosphoserine via aminotransferase; glutamate–>alpha-KG; OH replaced by a phosphate

Question 22

3rd step of Serine synthesis

Answer 22

3-Phosphoserine–>Serine via phosphatase; use a water, lose a Pi

Question 23

Name an essential component of the one carbon pool of metabolism

Answer 23

Tetrahydrofolate

Question 24

What happens to Serine in the presence of tetrahydrofolate and enzymes?

Answer 24

Take off the CH2OH and replace it with just a hydrogen=Glycine

Question 25

How is Glycine made from Serine?

Answer 25

Serine in the presence of H4folate uses a water and becomes Glycine.

Question 26

What is the difference between Serine and Cysteine?

Answer 26

The sulfur attached to the end of Cysteine

Question 27

Describe the steps involved in the normal breakdown of Methionine AND the synthesis of Cysteine from Serine with sulfur from Methionine

Answer 27

Mammals eat Methionine as an essential amino acid. In the presence of ATP, Methionine-->S-adenosylmethionione (sulfur attached to adenosine) via methionine adenosyltransferase. You can detach the methyl group from AdoMet making S-adenosylhomocysteine. Split that out and release adenosine to go back to make ATP. We have methionine minus a methyl group= Homocysteine. We bring in Serine from somewhere else and link it to homocysteine and transfer the sulfur group to make Cystathionine. Using an enzyme, take off the NH3 and you have Cysteine and alpha-Ketobutyrate.

Question 28

Which amino acid is needed to make purines and pyrimidines?

Answer 28

Glutamine. It donates nitrogens to nucleotdies.

Question 29

Carbon source for Alanine

Answer 29

Pyruvate (from glucose)

Question 30

Carbon source for Aspartate

Answer 30

OAA (from glucose)

Question 31

Carbon source for Glutamate

Answer 31

alpha-KG (from glucose)

Question 32

Carbon source for Serine

Answer 32

3-P-Glycerate (from glucose)

Question 33

For the nonessential amino acids, all but one can be made in mammals starting with glucose. Which one cannot?

Answer 33

Tyrosine

Question 34

How is the bioactive amine Histamine produced?

Answer 34

Decarboxylation of Histidine. Histamine causes dilation of blood vessels, bronchoconstriction, and secretion of HCl

Question 35

How is the bioactive amine Nitric Oxide (NO) produced?

Answer 35

From arginine by nitric oxide synthase. NO relaxes vascular and intestinal smooth muscles. Acts via cGMP.

Question 36

What bioactive amine acts as neurotransmitters?

Answer 36

Peptides

Question 37

Describe the synthesis of Creatinine

Answer 37

Arg, Gly, and Met can be made into Creatine which can be converted into Creatine-Phosphate using creatine kinases and ATP-->ADP. Spontaneously, Creatine-P can turn into Creatinine which is then filtered into the urine.

Question 38

What is measured in the blood clinically to estimate renal function?

Answer 38

Creatinine

Question 39

The bioactive amines Serotonin (AKA 5-HT) and Melatonin are derived from what?

Answer 39

Tryptophan

Question 40

Bioactive amine: describe the synthesis of Thyroxin

Answer 40

Thyroid hormones are produced by the iodinatin of tyrosine resides of thyroglobulin.

Question 41

Name two other Tyrosine products

Answer 41

Melanin (Tyrosinase deficiency results in albinism in chow chows) and it's a precursor to the quinone of CoQ. Thyroid deficiency can come from iodine deficiency.

Question 42

Bioactive amines: describe the synthesis of catecholamines

Answer 42

Neurotransmitters: Catecholamines include dopamine, norepinephrine, and epinephrine. They are all derived from Tyrosine (Methionine as methyl donor for epinephrine)

Question 43

How to recognize Dopamine, Norepinephrine, and Epinephrine molecules

Answer 43

They all the Tyrosine ring

Question 44

Which amino acid is a major stimulatory neurotransmitter in the CNS? And also a precursor for gamma-Aminobutyrate

Answer 44

Glutamate; GABA is a major inhibitory transmitter in the brain and synthesied via glutamate decarboxylase.

Question 45

Which amino acid is primarily found in inhibitory interneurons in the spinal cord, where it blocks impulses traveling down the cord in motor neurons to stimulate skeletal muscle?

Answer 45

Glycine (also participates in 1-carbon pool)

Question 46

What causes major problems (dilated cardiomyopathy, retinopathy, renal dz, fat emulsification/absorption, reproductive failure, and immune deficiency) in deficient cats?

Answer 46

Taurine

Question 47

What amino acid synthesizes taurine?

Answer 47

Cysteine