Functions of Biotin in the Vitamin B Complex group and its uses.
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- Biotin is a very important member of the B-Complex group of vitamins.
- Biotin was isolated in 1942 by Vincent du Vigneaud, who was awarded Nobel prize in 1955.
Sources of Biotin
- Normal bacterial flora of the gut provide adequate quantities of biotin.
- It is also distributed ubiquitously in plant and animal tissues.
- Egg yolk are rich sources.
Structure of Biotin
- It consists of an imidazole ring fused with a thiophene ring with a valeric acid side chain.
- The carboxyl group forms an amide linkage with the epsilon nitrogen of a lysine residue in the apo-enzyme.
Coenzyme activity of Biotin
- As with other members of the group, Biotin acts as a coenzyme for the carboxylation reactions.
- It captures a molecule of CO2, which is then attached to the nitrogen of the biotin molecule.
- This reaction needs energy which is provided by ATP.
- The activated carboxyl group is then transferred to the substrate.
Reactions that need Biotin as a coenzyme
1. Acetyl CoA carboxylase
- This enzyme adds CO2 to acetyl CoA to form malonyl CoA.
- This is the rate limiting reaction in biosynthesis of fatty acids.
- Acetyl CoA +CO2+ATP→ Malonyl CoA + ADP+Pi
2. Propionyl CoA carboxylase
- Propionyl CoA +CO2+ATP → Methyl malonyl CoA +ADP+Pi
3. Pyruvate carboxylase
- Pyruvate + CO2 + ATP → Oxaloacetate + ADP + Pi
- It provides the oxaloacetate, …
FOR COMPLETE LESSON OF BIOTIN, PLEASE CLICK THE VIATMINS TAB IN “BIOCHEMISTRY I”. THEN CLICK CURRICULUM TO VIEW THE LIST.