Question

A 7 year old female presents with anxiety, dizziness, sweating and nausea following brief episodes of exercise. These symptoms are relieved by eating and do not occur if the patient is fed frequently with small meals. She has hypoglycemia following brief fasting and alanine does not increase blood sugar. This condition is caused by a lack of activity of one enzyme. From the three enzymes listed below, which is the most likely one and briefly explain your reasoning. Also describe briefly why it could not have been one of the other enzymes. The three enyzmes are

a. Cytochrome c reductase

b. Pyruvate carboxylase

c. Hexokinase

Answer 1

Out of the three enlisted enzymes the condition is caused due to the lack of Hexokinase. This means option C is the correct answer. Hexokinase converts glucose which is a six-carbon compund to glucose-6-phosphate which is the main product for conduction glycolysis. Therefore, if hexokinase is deficient in the system then glucose-6-phosphate will not be formed. this will affect the cycle of glycolysis which provides energy to the body.

On the other hand, cytochrome c reductase is an enzyme in the electron transport chain that is used for the generation of ATP. Thus, it has no role in the breakdown of sugar inside the body. Similarly, Pyruvate c carboxylase is involved in the carboxylation of pyruvate which then forms oxaloacetate. thus, it acts on pyruvate after it has been produced. In order to make pyruvate it is important that the living body is able to perform glycolysis which is only possible if Hexokinase converts glucose to glucose-6-phosphate.