Amino acid metabolism Flashcards
1
Q
A
Nitrogen pool
2
Q
A
Tissue protein
3
Q
A
Urea cycle
4
Q
Transamination
A
Exchange of an amine group with a ketone group from another molecule
- Catalysed by transaminases
5
Q
What is the most frequent keto-acid involved in transamination?
A
Alpha-ketoglutaric acid
6
Q
Give an example of a transamination reaction
A
Alanine + alpha-ketoglutaric acid → Pyruvic acid + Glutamic acid
7
Q
Structure: Alanine
A
8
Q
Structure: α-ketoglutarate/α-ketoglutaric acid
A
9
Q
Structure: Pyruvic acid/Pyruvate
A
10
Q
Structure: Glutamic acid
A
11
Q
When is transamination seen?
A
During amino acid synthesis
12
Q
What are the ‘collection’ and ‘receiving’ agents for nitrogen?
A
- α-ketoglutarate
- Glutamic acid
13
Q
List some transaminases
A
- ASAT=GOT
- ALAT=GPT
14
Q
Location of ASAT=GOT
A
In the cytosol/mitochondrion of:
- Liver
- Heart
- Muscle
15
Q
Location of ALAT=GPT
A
In the cytosol/mitochondrion of:
- Liver
16
Q
Title the figure
A
Ketoglutaric + Glutamic acid
Synthesis of amino acids and other nitrogen bases
17
Q
A
Nitrogen bases
18
Q
A
Transamination
19
Q
A
Transamination
20
Q
A
Amino acid
21
Q
A
Ketoacid
22
Q
Cysteine is synthesised from…
A
- Methionine
- Serine
23
Q
Glycine is synthesised from…
A
Phosphoglyceric acid
24
Q
Which amino acids are essential in the chicken?
A
- Glycine
- Arginine
25
Give the relevance of essential amino acids in ruminants
Ruminants have no _essential_ amino acids
They are produced by rumen microbes
26
Oxidative deamination
Amino acid → Keto acid
* *Removal of amine functional group (NH3)*
* *Amin functional group is replaced by the ketone group*
27
Oxidative deamination occurs primarily on...
Glutamic acid
28
Glutamate dehydrogenase is allosterically controlled by...
* ATP (Inhibitor)
* ADP (Activator)
29
Title the figure
Oxidative deamination
30
Once keto acids have been formed, they can be used for...
Metabolism into CO2 + H2O
## Footnote
*Via Citric acid cycle*
31
Amino acids converted into acetyl-CoA can be converted into...
Ketone bodies
32
Title the figure
The fate of Amino acid carbon skeletons
33
Amino acids producing pyruvate
* Alanine
* Glycine
* Cysteine
* Serine
34
Amino acids producing acetyl-CoA
* Isoleucine
* Leucine
* Tryptophan
35
Amino acids producing oxaloacetate
* Aspartic acid
* Asparagine
36
Amino acids producing fumarate
* Tyrosine
* Phenylalanine
* Aspartic acid
37
Amino acids producing succinyl-CoA
* Isoleucine
* Methionine
* Threonine
* Valine
38
Acetoacetyl CoA
39
Amino acids producing acetoacetyl-CoA
* Leucine
* Lysine
* Phenylalanine
* Tyrosine
40
Amino acids producing α-ketoglutarate
* Glutamic acid
* Glutamine
* Histidine
* Proline
* Arginine
41
Ammonia is produced via...
* Oxidative deamination
* Degradation of biogenic amines
* Absorption from the GI tract
42
Ammonia is detoxified via...
* Urea cycle
* L-Glu synthesis
* Gln + Asn synthesis
* Kidney: Glutaminase activity
* Purine synthesis: Uric acid (Birds)
43
Which species lack the urea cycle?
Birds
## Footnote
*They do not possess the arginase enzyme*
44
Portosystemic Shunt
* Blood of portal vein enters the vena cava, _not the liver_
* Ammonia toxicosis risk
* Seen in Yorkshire terrier
45
Title the figure
Glutamine synthesis + Degredation
46
Reaction: Decarboxylation of amino acids
Amino acid → Amine
## Footnote
*Amino acid decarboxylase*
47
Decarboxylation of Histidine
Histidine → Histamine
## Footnote
*Histidine decarboxylase*
48
Decarboxylation of Tyrosine → Catecholamines
Tyrosine → DOPA → Catecholamines
## Footnote
*Dihydroxyphenylalanine (DOPA) decarboxylase*
49
Decarboxylation of Tyrosine
Tyr → Tyramine
*Tyrosine* *decarboxylase*
50
Decarboxylation of: 5-OH-Trp
5-OH-Trp → Serotonin
## Footnote
*5-OH tryptophane decarboxylase*
51
Decarboxylation of Glutamate
Glutamate → Gamma-amino-butyrate (GABA)
## Footnote
*Glutamate decarboxylase*
52
Decarboxylation of: Serine
Serine → Ethanolamine (Cholamine)
*Serine decarboxylase*
53
Decarboxylation of: Cysteine
Cysteine → Cysteamine
## Footnote
*Cys-decarboxylase*
54
Decarboxylation of: Cysteine → Taurine
Cysteine → cysteic acid → Taurine
55
Decarboxylation of Aspartic acid
Aspartic acid → Beta-alanine
## Footnote
*Asp-decarboxylase*
56
What is the role of taurine in bile salt synthesis?
_Bile acids_ are conjugated with taurine to produce _bile salts_
57
Decarboxylation of: Ornitine
Ornitine → Putrescine
## Footnote
*Ornithine-decarboxylation*
58
Decarboxylation of: Lysine
Lysine → Cadaverine
## Footnote
*Lysine-decarboxylase*
59
Cadaverine
* Foul smelling
* Produced by protein hydrolysis during putrefaction
60
Location of carnosine
Muscle + Brain (Mammals)
61
Location of Anserine
Muscle + brain (birds)
62
The function of carnosine and anserine
Buffering lactic acid + RBCs
63
Function of glutathione
* Splits disulphide bonds of proteins (reduction)
* Reduces thioredoxine
64
Glutathione removes peroxides via which enzyme?
Glutathione peroxidase
