Biotin

Question 1

Why does consuming egg whites not contribute much biotin

Answer 1

A protein called avidin in raw egg whites binds to biotin and prevents absorption

Question 2

When protein bound how is biotin absorbed

Answer 2

Digested by proteolytic enzymes

Pepsin, proteases/peptidases, and biotinidase

Question 3

Where is biotin from food absorbed

Answer 3

Absorbed mainly in jejunum, followed by ileum

Question 4

What are the 3 non-coenzyme roles of biotin

Answer 4

Biotinylation of proteins (histones)

Stimulates expression of glucokinase

Inhibits expression of phosphoenolpyruvate

Important for normal progression of the cell cycle

Question 5

What is the biotinylation of proteins

Answer 5

Biotin attaches to histones

Question 6

Glucokinase function

Answer 6

Traps glucose inside cell

Question 7

What is biotin involved in degradation of

Answer 7

Amino acids

Question 8

What are the 4 carboxylate a that use biotin as a cofactor

Answer 8

Pyruvate carboxylase*

Acetyl CoA carboxylase*

Propionyl-CoA carboxylase

Beta-methylcrotonyl-CoA carboxylase

Question 9

What are major sources of biotin

Answer 9

Beef, soybeans, egg yolk, cereals and nuts

And it’s made by bacteria in large intestine