Biotin is a B vitamin that acts as a coenzyme in carboxylation reactions in the body. It is found naturally in many foods like nuts, dairy, eggs, and vegetables. In the body, biotin functions to help metabolize fats and amino acids. It also plays roles in immune function, hair and nail growth, and healthy skin. Deficiencies can result from raw egg consumption due to biotin binding by the protein avidin in eggs. Biotin is used diagnostically to detect deficiencies and in techniques like ELISA and DNA labeling using its strong binding to avidin and streptavidin.

1. BIOTIN
VYDEHI VEERAMALLA
FINAL YEAR PG
BIOCHEMISTRY

2. • Introducyion
• Chemistry
• Functions
• Food sources
Contents
• Deficiency
• Biotin antagonists
• Diagnostic uses
• Recent advances

3.  anti-egg white injury factor
 vitamin H – ‘H’ stands for ‘haut’,
 the German word for skin.
 Co-enzyme R is essential for Rhizobium, in root
nodules of Leguminous plant
 Water soluble B-vit
 Sulphur containing
Introduction

4. heterocyclic monocarboxylic acid,

5. Biocytin is coenzyme
Carboxybiotin

6. Coenzyme for carboxylase
 Pyruvate carboxylase
 Acetyl CoA carboxylase
 Propionyl carboxylase
 β - Methyl crotonyl CoA carboxylase

7.  All the carboxylation reactions in the biological system are
not dependent on Biotin
 Few carboxylation reactions which do not require biotin
1) Formation of carbamoyl phosphate in urea cycle
2) Incorporation of CO2 in purine synthesis

8. 1) Immune system
2) Growth of hair
3) Proper distribution of colour pigment
4) Nervous system
Functions of Biotin

9. Pyruvate carboxylase

10. Fatty acid synthesis
Acetyl co A carboxylase

11. β - Methyl crotonyl CoA carboxylase
Leucine metabolism

12. Propionyl CoA Carboxylase

13. Water-soluble
SWISS CHARD SASKATOON BERRIES
PEANUTS
MOLASSES
HONEY

14. • water-insoluble form
kidney, milk
cereals
beans
vegetables

15. water-insolubleform
milk
Egg yolk
liver

16. Intestine bacteria can synthesise the vitamin and is a good source
STORAGE liver.
Excretion:urine, faeces and milk
RDA
Adults : 200 – 300 mg/day

17.  generally not seen because of wide distribution in foods
 Synthesis of vitamin by the bacterial flora in the gut
causes
a) 20 raw eggs/day
b) sulfonamides

18. Biotinidase is required to salvage biotin for reuse during
cellular turnover.
It is also needed to release bound ingested biotin for
absorption.
A shortage of the enzyme results in a greater requirement
for the vitamin than normal.

19. Inherited - Autosomal recessive
Holocarboxylase synthetase deficiency & Biotinidase deficiency
high levels of organic acids in urine.
Blood tests can then be done on white cells & plasma to measure enzyme levels.
biotin responsive dermatoses

20. Leiner’s disease/erythroderma desquamativum or
exfoliative dermatitis
breastfed infants with
persistent diarrhoea.
low biotin content of
human milk
 poor absorption of
biotin due to diarrhoea

21. thick, frizzy, light-colored hair which simply
will not respond to combing.
uncombable hair syndrome

23. Brittle nails
conjunctivitis dermatitis
Easy peeling of skin

24. • Avidin ( Raw egg white injury factor )
• a heat labile protein
• Egg white contains Avidin & egg yolk contains biotin
• Avidin binds to biotin & makes its unavailable for
absorption
• Avidin is inactivated by boiling the eggs & biotin is
readily absorbed when boiled eggs are used in diet

25.  One molecule of avidin can combine with four molecules of
biotin
 Avidin-biotin system is commonly utilized for detection of
pathogens in ELISA test

26. Biotin Conjugates used with Avidin or Streptavidin
for Maximum Signal Enhancement:
Unlabeled streptavidin (S)
(L) i.e. an enzyme or analyte, which also contains multiple biotin
moieties.
This effect results in an extended polymeric structure that maximizes
sensitivity in many assays.

27. If a 5′-biotinylated primer is used in a PCR reaction the corresponding strand of the PCR
product will be biotinylated.
It can be separated from the unbiotinylated complementary strand by exposure to
streptavidin-coated magnetic beads
This is a useful technique for isolating one strand of a PCR product for further
manipulation.
Biotin labelling ofDNA

28. 1. Biotin is sulphur containg
2. water soluble
3. B- vitamin
4. widely distributed in food
5. Used in Elisa
6. Dna labelling
summary

29. Thankyou