Lecture #17 - Biotin

Question 1

What condition led to the discovery of Biotin?

Answer 1

Research into ‘egg white injury,’ characterized by hair loss, dermatitis, and neuromuscular problems from eating raw eggs.

Question 2

How is Biotin found in our bodies?

Answer 2

As Biotinyllysine.

Question 3

What are the primary functions of Biotin in metabolism?

Answer 3

It functions as a mobile carboxyl carrier in four carboxylase enzymes:

Pyruvate carboxylase (gluconeogenesis)
acetyl-CoA carboxylase (lipid synthesis)
propionyl-CoA carboxylase (protein metabolism; synthesis of amino acids)
Beta-methyl-crotonyl-CoA carboxylase

*need to move carbons from one molecule to another to build something

Question 4

Why can consuming raw eggs lead to a Biotin deficiency?

Answer 4

Raw eggs contain a protein named avidin that irreversibly binds biotin, preventing its absorption.

Question 5

How can the issue with avidin and Biotin absorption be resolved?

Answer 5

Avidin is heat labile (destroyed by heat), so cooking eggs resolves the potential problem of biotin absorption