Which statement correctly distinguishes hepatic glucokinase from hexokinase?
- A Glucokinase has a low Km for glucose and is inhibited by its product glucose-6-phosphate
- B Glucokinase acts on all common hexoses whereas hexokinase is specific for glucose
- C Glucokinase has a high Km for glucose and is transcriptionally induced by insulin ✓
- D Glucokinase is expressed in nearly all tissues whereas hexokinase is liver specific
Correct answer: C. Glucokinase has a high Km for glucose and is transcriptionally induced by insulin
Explanation
Glucokinase (hexokinase IV) has a high Km for glucose, shows sigmoidal kinetics, is not inhibited by glucose-6-phosphate, and its gene expression is upregulated by insulin in the fed state. This suits the liver, which must handle large portal glucose loads. Hexokinase I to III have low Km, are product inhibited, and are widely distributed, which eliminates the other three statements.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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