Does glucose-6-phosphate allosterically inhibit glucokinase AT ALL?

Expert Solution

Answer:

Glucokinase is an iso-enzyme of hexokinase which is a key glycolytic enzyme. Glucokinase is primarily found in liver cells and also in small quantities in the beta cells of the pancreas as well where hexokinase is absent. It has low affinity to glucose hence acts only when there is an abundance of glucose available in the liver. It has a higher Km for glucose than hexokinase. That is, it acts only when blood glucose level is more than 100mg/dl.

Glucokinase is not inhibited allosterically by glucose 6 phosphate. This is because it phosphorylates glucose only when there is an abundance of glucose and plays its chief role in making glucose 6 phosphate available for glycogen synthesis.Since it has a low affinity for glucose, during the limited supply of glucose it ensures that the brain and muscles receive whatever quantity of glucose is available.

It is hexokinase that is allosterically inhibited by glucose 6 phosphate and not glucokinase.

gladiator answered 1 year ago

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