Amino acid biosynthesis Flashcards
Can essential amino acids be synthesised de novo?
No. They must be obtained from the diet.
What are the non- essential amino acids?
From a-keto acids:
-Alanine (A)
- Aspartic acid (D)
- Glutamic acid (E)
From amidation:
- Asparagine (N)
- glutamine (Q)
From cyclization of glutamate:
- Proline (P)
From hydroxylation of Phenylalanine:
- Tyrosine (Y)
Last 3:
- Glycine (G)
- Serine (S)
- Cysteine (C)
What physiologically active amines are derived from amino acids?
- GABA
- Histamine
- Serotonin
- Epinephrine
- Norepinephrine
- Dopamine
What is the precursor of GABA?
Glutamate, via glutamate decarboxylase
What is the precursor of Histamine?
Histidine, via histidine decarboxylase
What is the precursor of Serotonin?
Tryptophan, via 5-hydroxytryptophan
What inactivates the catecholamines?
Catecholamines inactivated by oxidative deamination by MAO & O-methylation by COMT.
*MAO = Monamine oxidase
*COMT = Catechol-O-methyltransferase
How are the aldehyde products oxidised?
They’re oxidised to their corresponding acids.
What causes an excessive production of catecholamines?
It is caused by ^ in homovanillic acid (VMA) which is caused by increased tumours of the adrenal glands.
What is the pharmacological use of MAO inhibitors?
They’re used as anti-depressants.
