7. Functions
1. Act as Coenzymes in Transamination reactions
1. Act as Coenzymes in Decarboxylation reactions
8. 3. Act as Coenzymes in many reactions
a) Glutamate GABA (deficiency leads to Convulsions)
b) Tryptophan Serotonin (cerebral activity)
c) Tryptophan Melatonin (cardiac rhythm)
d) Histidine Histamine (vasodilator)
e) Tyrosine catecholamine (neurotransmitters)
4. Heme synthesis
Aminolevulinic acid synthase is a PLP dependent enzyme, which
is the rate limiting step in heme synthesis. Therefore deficiency
may result in Anaemia.
9. 5. Act as Coenzymes in production of Cysteine from Serine.
10. RDA = 1-2 mg / day
Pregnancy , lactation and old age = 2.5 mg/day
Nutritional Requirement
Assay of Vitamin B6
Activities of erythrocyte transaminases have been used frequently as indirect
measurements of Vitamin B6 status
13. Toxicity
Excess of 2-7g of Pyridoxine per day- Sensory Neuropathy and skin lesions
Other reports, Excess of 100-200 mg/day- Neurological damage
14. BUZZ
What is the active form of Vitamin B6?
A. Pyridoxine
B. Pyridoxal
C. Pyridoxamine
D. Pyridoxal phosphate
15. All manifestations are seen in Vitamin B6 deficiency,
except
A. Skin rashes as in pellagra
B. Macrocytic anaemia
C. Peripheral neuritis
D. Convulsions in children
16. CASE STUDY
25 year old woman presented with neurological manifestations like depression,
irritability, nervousness, confusion and convulsions. Biochemical investigations
revealed-
- Hypochromic microcytic anaemia
- Xanthenuric acid in urine
1. What is the probable diagnosis?
2. Name the coenzyme form of the vitamin and write two reactions catalyzed by
the coenzyme.
3. Give the basis of neurological disorders.
