Question

Biochemistry help

1) Write the names of the degradative and the biosynthetic enzymes of glycogen metabolism that are targeted to regulate glycogen metabolism.

2) ) Discuss, by drawing structures, how hormones regulate the enzymes you name in Question 1.

3) Discuss, with structures, the reactions of the non-oxidative phase of the pentose phosphate pathway and show how the non-oxidative phase is used to synthesize all the pentoses in nature.

Answer 1

1. The glycogen remains as a stored form of energy by the liver and skeletal muscles. The stored glycogen within liver help to regulate blood glucose level, while as it acts as a source of energy in the muscles during muscle contraction. The degradation of glycogen into glucose is known as glycogenolysis and formation of glycogen from glucose is known as glycogenesis.

A) Glycogenolysis or glycogen degradation: The various enzyme-catalyzed steps involved in this process are:

1. Glycogen phosphorylase: This sequentially removes units of glucose from glycogen molecule by breaking α1–4 glycosidic bonds.
2. Phosphoglucomutase: converts glucose 1-phosphate to glucose 6-phosphate
3. Glucose 6-phosphatase (Liver): Converts glucose 6-phosphate to glucose

B) Glycogenesis or glycogen formation: : The various enzyme-catalyzed steps involved in this process are:

1. UDP-glucose pyrophosphorylase: This leads formation of UDP-glucose from UTP an glucose 1-phosphate
2. Glycogen synthase: Converts UDP-glucose into glycogen

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