Biotin

Question 1

How is biotin recycled?

Answer 1

Holocarboxylase synthetase is going to attach biotin to the enzyme. These are active holocarboxylases, which go on and participate in different reactions.

Once the enzymes are no longer needed, they go through proteolytic degradation.

The BIOTINIDASE enzyme can cleave off any AA residue attached to biotin and allow biotin to be recycled.

Question 2

Explain the biotinylation of histones.

Question 3

Histones

Answer 3

A family of proteins that associate with DNA in the nucleus and help condense it into chromatin.

Question 4

What allows histones to associate with DNA?

Answer 4

The histones are positively charged, while DNA is negatively charged.

Question 5

Nucleosomes

Answer 5

Appears like beads on a string under a microscope, the beads are nucleosomes.

Each nucleosome is made of DNA wrapped around eight histone proteins that function like a spool

Question 6

N-Terminal tail

Answer 6

Each of the histones has a tail, an N-terminal tail. These tails hang off and are modified by different possibilities that affect gene expression, such as biotinylation.

Question 7

Biotinylation

Answer 7

the process of attaching biotin to enzymes

Question 8

(TRUE/FALSE) For the coenzymes that catalyze the carboxylase reactions, the enzymes themselves are modified, so that biotin is attached to the enzyme itself.

Answer 8

TRUE

Via HOLOCARBOXYLASE SYNTHETASE enzyme attaches the enzyme to biotin via COVALENT BONDS