Amino Acid Metabolism Flashcards

(39 cards)

1
Q

The basic structural units of proteins are

A

amino acids

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2
Q

There are …. common amino acids found in proteins

A

20

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3
Q

What is an α carbon?

A

it is a tetrahedral carbon at the centre of an amino acid

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4
Q

Describe the basic amino acid structure

A
  • α-Carbon is chiral (except in glycine)
  • at pH of 7.0, uncharged amino acids are zwitterions
  • they have a tetrahedral structure
  • α-carbon is bonded to an amino group(NH2) and a carboxyl group(COOH) on the other side
  • a 3rd bond is always to H and the 4th bond is to a variable side chain(R)
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5
Q

6 properties of amino acids

A
  1. capacity to polymerize
  2. novel acid-base properties
  3. varies structure and chemical functionality
  4. chirality
  5. differ from each other by the R group
  6. R group influences solubility in water
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6
Q

The 5 main classes of the common amino acids based on the reactivities of their R groups

A
  1. Aliphatic non-polar
  2. Aromatic
  3. Polar uncharged
  4. Polar negatively charged
  5. Polar positively charged
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7
Q

Name all the aliphatic non-polar amino acids

Clue: GAVLIPM

A
Glycine
Alanine
Valine
Leucine
Isoleucine
Proline
Methionine
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8
Q

Name the aromatic amino acids

Clue: PTT

A
  1. Phenylalanine
  2. Tryptophan
  3. Tyrosine
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9
Q

Name the polar uncharged amino acids

Clue: STCAG

A
  1. Serine
  2. Threonine
  3. Cysteine
  4. Asparagine
  5. Glutamine
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10
Q

Name the polar negatively charged amino acids

Clue: AG

A
  1. Aspartate

2. Glutamate

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11
Q

Name the polar positively charged amino acids

Clue: LAH

A
  1. Lysine
  2. Arginine
  3. Histidine
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12
Q

How are amino acids classified based on nutritional requirement?

A

Essential
Non-essential
Semi-essential

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13
Q

Name the essential amino acids

Clue: HILL MPT TV

A
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
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14
Q

Name the non-essential amino acids

Clue: 4A C 3G PST

A
Alanine
Arginine
Asparagine
Aspartate
Cysteine
Glycine
Glutamine
Glutamate
Proline
Serine
Tyrosine
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15
Q

Name the semi-essential amino acids

Clue: ACGGPT

A
Arginine
Cysteine
Glutamine
Glycine
Proline
Tyrosine
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16
Q

When is Methionine produced in large amounts?

A

When cysteine is not adequately supplied in the diet, to produce cysteine

17
Q

When is Phenylalanine produced in large amounts?

A

when tyrosine is adequately supplied in the diet, it is needed to form tyrosine

18
Q

How are amino acids groups based on catabolic intermediates?

A

Glucogenic and Ketogenic

19
Q

What are glucogenic amino acids catabolized to?

A
pyruvate
α-ketoglutarate
fumarate
succinyl CoA
oxaloacetate
20
Q

Examples of glucogenic amino acids

Clue: 4A C GH MPTV

A
Alanine
Arginine
Asparagine
Aspartate
Glutamine
Histidine
Methionine
Proline
Threonine
Valine
21
Q

What are ketogenic amino acids catalyzed to?

A

acetyl CoA and acetoacetyl CoA

22
Q

Purely ketogenic amino acids

Clue: 2L

A

Leucine

Lysine

23
Q

Both glucogenic and ketogenic amino acids

Clue: IPTT

A

Isoleucine
Phenylalanine
Tryptophan
Tyrosine

24
Q

What are unusual amino acids?

A

they are formed from the modification of common amino acids

25
3 examples of unusual amino acids
hydroxyproline ornithine norleucine
26
What are the 4 general reactions of amino acids?
1. Decarboxylation 2. Transamination 3. Oxidative deamination 4. Transdeamination
27
Amino acids are decarboxylated to form ..........
amines. eg. 1. Histamine from Histidine 2. L-Dopa from Tyrosine 3. Serotonin from Tryptophan
28
What is transamination?
transfer of amino group from an amino acid to an α-keto-acid to from the corresponding amino acid
29
What enzyme catalyzes transamination and what prosthetic group does it require?
amino transferases | requires pyridoxal phosphate (PLP), a derivative of vitamin B6
30
What's the function of PLP?
it is an intermediate carrier of the amino groups at the active site of amino transferase
31
What type of transformation does PLP undergo?
reversible transformation between the aldehyde form and the aminated form, pyridoxamine phosphate
32
In mammals, which amino acids can't be transaminated?
Lysine | Threonine
33
What type of reaction can't proline participate in and why?
PLP dependent reactions including transamination and decarboxylation because it has a secondary amino group
34
Where does oxidative deamination of glutamate occur?
mitochondria of the liver cells
35
What are the products of oxidative deamination of glutamate and which enzyme catalyzes the reaction?
α-ketoglutarate and ammonium ions | glutamate dehydrogenase is the enzyme
36
When does glutamate dehydrogenase activity increase?
when hepatocytes require fuel from TCA
37
What are the allosteric activators and inhibitors of glutamate dehydrogenase?
AA- GDP& ADP | AI- GTP&ATP
38
What is transdeamination?
the combined action of amino transferases and glutamate dehydrogenase
39
What does the coupling of oxidative deamination and transamination do?
creates an avenue for deaminating all amino acids