What do hexokinase and glucokinase have in common?
Glucokinase and Hexokinase are enzymes which phosphorylate glucose to glucose-6-phosphate, trapping glucose inside the cell.
What reactions do hexokinase and glucokinase catalyze?
Both hexokinase and glucokinase catalyze the same reaction of glycolysis. Hexokinase is present in almost all tissues while glucokinase is present in the liver and beta cells of the pancreas. They use ATP to convert glucose into glucose 6-phosphate.
Where is hexokinase and glucokinase found?
Glucokinase, an Isoenzyme of Hexokinase. Glucokinase (hexokinase D) is a monomeric cytoplasmic enzyme found in the liver and pancreas that serves to regulate glucose levels in these organs.
What is the Km value of hexokinase and glucokinase?
Glucokinase: Km = 10 mM, not inhibited by glucose 6-phosphate. Present in liver and in pancreas b cells. Hexokinase: Km= 0.2 mM, inhibited by glucose 6-phosphate. Present in most cells.
Does the liver have both glucokinase and hexokinase?
The liver, in addition to having hexokinase, also has another enzyme- glucokinase. These two enzymes catabolize the same reaction. The only difference is that glucokinase is found only in the liver. That means hepatocytes have both hexokinase and glucokinase.
What type of reaction is hexokinase?
Hexokinase is the initial enzyme of glycolysis, catalyzing the phosphorylation of glucose by ATP to glucose-6-P. It is one of the rate-limiting enzymes of glycolysis. Its activity declines rapidly as normal red cells age.
What is the main function of hexokinase?
What is the Km of glucokinase?
What is the function of glucokinase?
Glucokinase functions as the glucose sensor in the beta cell by controlling the rate of entry of glucose into the glycolytic pathway (glucose phosphorylation) and its subsequent metabolism. In the liver, glucokinase plays a key role in the ability to store glucose as glycogen, particularly in the postprandial state.
What does Michaelis constant tell us?
Km is the Michaelis-Menten constant which shows the concentration of the substrate when the reaction velocity is equal to one half of the maximal velocity for the reaction. It can also be thought of as a measure of how well a substrate complexes with a given enzyme, otherwise known as its binding affinity.
What does a lower Km value mean?
It indicates the affinity of an enzyme for a given substrate: the lower the KM value, the higher the affinity of the enzyme for the substrate.
How do you plot a Michaelis-Menten graph?
Plotting the Michaelis-Menten Curve Label the x-axis mM of [S] or concentration of substrate. Label the y ax- sec/micro-mole of V or velocity of reaction. Insert different values of [S] into the Michaelis-Menten equation, along with the values found for Km and Vmax, to solve for V.