Hexokinase IV has a Km value that is substantially higher than the Km for other
ID: 67054 • Letter: H
Question
Hexokinase IV has a Km value that is substantially higher than the Km for other hexokinases. What is the significance of this fact?
The higher Km reflects lower affinity for its substrate, and therefore this kinase is only operational when glucose levels are low.
The higher Km reflects higher affinity for its substrate, and therefore this kinase is only operational when glucose levels are low.
The higher Km reflects lower affinity for its substrate, and therefore this kinase is only operational when glucose levels are high.
The higher Km reflects high affinity for its substrate, and therefore this kinase is only operational when glucose levels are high.
Explanation / Answer
If the Km is high then the affinity of an enzyme to substrate is low. In contrast, if the Km is low the affinity of an enzyme to substrate is high. Thus, the enzyme with high Km needs large concentration of substrate has to reach half of Vmax.
Hence, the correct option among the following is 3rd one.