Synthesis of amino acids Flashcards Preview

ER Biochem > Synthesis of amino acids > Flashcards

Flashcards in Synthesis of amino acids Deck (10)
Loading flashcards...
1
Q

Describe the synthesis of amino acids from phenylalanine

A
2
Q

What does epinephrine and norepinephrine break down into

A

VMA: vanillymandelic acid

Pheochromocytoma leads to increased VMA

3
Q

What does dopamine break down into

A

HMA: homovanillic acid

4
Q

Describe the synthesis of serotonin

A
  • Serotonin is synthesized in the gut, platelets and CNS
  • Synthesized from tryptophan
  • Serotonin is metabolized to 5-HIAA by MAO
5
Q

Describe the steps of tryptophan to serotonin

A
6
Q

Describe carcinoid syndrome

A
  • Tumor of serotonin producing cells in GIT (APUD cells)
  • Cutaneous flushing, sweating, diarrhea, bronchospasm
7
Q

Describe tetrahydrobiopterin

A
  • Reactions using THBP
    • Phenylalanine hydroxylase (converts Phe to Tyr)
    • Tyrosine hydroxylase (converts Tyr to DOPA)
    • Tryptophan hydroxylase (converts Trp to 5-hydroxy tryptophan)
8
Q

Describe tetrahydrobiopterin deficiency

A
  • Results in hyperphenylalaninemia and decreased synthesis of neurotransmitters
    • Severe mental impairments and seizures
9
Q

Describe the steps in formation of thyroid hormone

A
  • Trapping iodine in the thyroid cell
  • Iodination of the thyroglobulin protein
  • Coupling of the iodinated Tyrosine side chains
  • Release of thyroid hormone
  • De-iodination of T4 to the active T3 form

Example of post translational modification

10
Q

Describe the function of thyroperoxidase

A
  • TPO fixes iodine to thyroglobulin
  • Next TPO acts as a peroxidase
    • Objective is to link two iodo-tyrosine side chains together