Tryptophan metabolism

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What are the specialized products formed by tryptophan in body.

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Terms in this set (10)

What are the specialized products formed by tryptophan in body.

Serotonin, Melatonin, Niacin

Coenzyme required for tryptophan hydroxylase

Tetrahydrobiopterin

Which vitamin is required for tryptophan metabolism

Vitamin B6 ( coenzyme for dopa decarboxylase)
Folic acid, Vitamin B12 for SAM formation

Which amino acid is used by pineal gland to form sleep inducing hormone in response to darkness or low light levels

Tryptophan for melatonin

A 40-year old male presents with flushing diarrhoea, abdominal pain and dry cough.
Endoscopy guided biopsy and urinary level of 5HIAA proved the diagnosis of carcinoid syndrome.Which one of the following enzymes is required for 5HIAA formation from serotonin?
Dopa decarboxylase
Tryptophan hydroxylase
MAO-A

MAO-A

Tryptophan

A 40-year old male presents with flushing diarrhoea, abdominal pain and dry cough.
Endoscopy guided biopsy and urinary level of 5HIAA proved the diagnosis of carcinoid syndrome. He is at risk of developing which of vitamin deficiency diseases?

Pellagra
In carcinoid syndrome , most of body tryptophan is directed towards serotonin formation and inadequate supply of tryptophan for niacin leads to pellagra.

A 40-year old male presents with flushing diarrhoea, abdominal pain and dry cough.
Endoscopy guided biopsy reveals carcinoid tumor.Which one of the metabolites will be most likely raised in 24 hour urine sample?
Tryptophan
5HIAA
N acetyl Serotonine

24 -hour Urinary 5HIAA is raised in patient with carcinoid syndrome

What is weight ration of tryptophan to niacin synthesis

60: 1
60 mg of tryptophan leads to 1 mg of niacin formation.

A person is given loading dose of tryptophan and urinary excretion of xanthuric acid increases.Which vitamin is deficient in him?

Kynureninase ( enzyme in tryptophan metabolism) requires PLP. When Vitamin B6 is deficient, metabolites ( 3-hydroxykynurenine)enter another minor pathway leading to Xanthuric acid production.(see the attached figure)