Vitamin B1 - Thiamine

Question 1

origin of B1

Answer 1

• mainly microbial synthesis in intestine by yeast or fungi
• plant origin: outer layer of grains
• animal origin: TPP -> B1

Question 2

where is B1 needed in the body

Answer 2

liver, kidney, nerve cells, RBC, cardiac mm.

Question 3

excretion

Answer 3

thiasol + pyrimidine -> thiamine pyrimidine to be excr. in the urine

Question 4

needed for degradation

Answer 4

PPP -> phosphatase used in fascilitated diffusion

Question 5

biochemical role

Answer 5

1. TPP is needed as cofactor in oxidative decarboxylation of Alpha-keto acids (pyruvate->AcCoA, AKG->succinylCoA)
2. cofactor of transketolase in PPP (ribose-5-P -> Fructose-6-P)

—> very imp for glucose metabolism; neuromuscular damage!!

Question 6

deficiency

Answer 6

beriberi:
- neuromuscular damage
- damage in TCA will lead to damage in organs
- wet form: odema from cardiac muscle damage
- dry form: neuromuscular damage

Question 7

deficiency in which spp. are important

Answer 7

1. pultry: polyneuritis(peripheral nerve damage), neuromuscular damage
2. RU: sep. of pyrimidine + Thiazol
3. fur bearing animals: raw fish with thiaminase (chastek’s paralysis)

Question 8

vit. antagonists

Answer 8

thiaminase
- fern is a source: pyrithiamine, which makes pyrimidine want to bind purine instead of thiazol -> cerebrocortical necrosis - CNS symptoms