Question
Which one of the following coenzyme is associated with glycogen phosphorylase:
| A. |
Thiamine pyrophosphate
|
| B. |
Tetrahydrofolate
|
| C. |
Flavin mononucleotide
|
| D. |
Pyridoxal phosphate
|
Show Answer
|
Correct Answer � D
Explanation
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|
Glycogen phosphorylase has a pyridoxal phosphate (PLP, derived from Vitamin B6) at each catalytic site.
Pyridoxal phosphate links with basic residues and covalently forms a Schiff base.
Once the Schiff base linkage is formed, holding the PLP molecule in the active site, the phosphate group on the PLP readily donates a proton to an inorganic phosphate molecule, allowing the inorganic phosphate to in turn to be deprotonated by the oxygen forming the α-1,4 glycosidic linkage.
