A healthy 28-year-old woman exhibits a peak serum glucose concentration of 220 mg/dL within 30 minutes of the consumption of 75 g of glucose. Two hours after ingestion, her serum glucose concentration decreases to 100 mg/dL. The uptake and trapping of glucose within liver cells at high serum glucose concentrations is facilitated by which of the following enzymes?

Question

Quizplus · Accepted Answer

Glucokinase is an enzyme that facilitates the uptake and trapping of glucose in liver cells by phosphorylating glucose to glucose-6-phosphate, especially at high serum glucose concentrations. Hepatic glucokinase has a high K_m for glucose in order to ensure that the liver does not trap glucose before sufficient levels are obtained in the blood. As the level of blood glucose increases, glucokinase will become more active resulting in phosphorylation of more glucose thus, trapping it in the cell leading to a gradual reduction in blood glucose levels.

A Healthy 28-Year-Old Woman Exhibits a Peak Serum Glucose Concentration