Question

1. What is the function of glyc. phosphorylase?

2. How would the Vmax of glyc. phosphorylase be affected if glycogen in the muscles begin to decrease?

Answer 1

Glycolysis is turned off due to hight ATP levels and glucose molecules are combined in long chains to form glycogen which is the animal carbohydrate storage product, this process is known as glycogenesis.
When blood glucose level drop splitting of glycogen occurs which is termed as glycogenolysis. The enzyme glycogen phosphorylase oversees phosphorylation and cleavage of glycogen to release glucose-1-phosphate which is then converted into glucose-6-phosphate which then enters the glycolytic pathway and get oxidized for energy.
1. Glycogen phosphorylase enzyme break down the bonds towards the end of the glucose residue that is glycogen and substitutes the phosphoryl group into it to release the glucose-1-phosphate.
2. Glycogen phosphorylase is an enzyme which is debranching enzyme and used in splitting of glycogen to produce glucose for energy need but when the glycogen level in the muscles decreases, Vmax will also decrease because the amount of glycogen phosphorylase is directly proportional to the amount of glycogen available.
Figure no. 1 :- Following process activates glycogen breakdown.

Figure no. 2 :- Glycogenolysis.

NOTE :- The compounds are listed in blue colour and enzymes are listed in black colour in the above pathways.