Glycogenesis and glycogenolysis

Question 1

Pathway for glycogenesis

Answer 1

Location: Liver contains GLUT 2 transporter and Glucokinase enzyme
1. Glucose – glucokinse – Gluc-6-P
2. Gluc-6-P – phosphoglucomutase – Gluc-1-P
3. Gluc-1-P – UDP glucose pyrophosphorylase – UDP glucose
4. UDP glucose –glycogen synthase – transfer of glucose to alfa 1-4 linkage
5. after eight subunit of glucose residue added in alfa 1-4 chain – transglycosylase – add glucose to branch of alfa 1-6 linkage

–Finally produces glycogen - polymer of glucose

Question 2

Pathway for glycogenolysis

Answer 2

1. Glycogen – glycogen phosphorylase– Gluc-1-P
2. Gluc-1-P – phosphoglucomutase – Gluc-6-P
3. Gluc-6-P –Gluc-6-phosphatase – Glucose (release in blood)

To remove branch glucose residue
debranching enzyme –transglycosylase – break alfa 1-4 linkage until 3-4 unit left then break alfa 1-6 linkage and move glucose residue to adjacent alfa 1-4 linkage until one residue left in 1-6 linkage which is removed by glucosidase to continue phosphorylation into Gluc-1-P