Hexokinase I-III
Cofactors used
Clinical / pharmacological. GCK mutations: MODY2; HK1 deficiency: haemolytic anaemia
What it does, reaction by reaction
Glycolysis Carbohydrate Metabolism · Cytosol
Glucose + ATP -> glucose-6-phosphate + ADP
Converts Glucose into Glucose-6-phosphate
› Notes
Hexokinase I–III in most tissues, or glucokinase (hexokinase IV) in liver and pancreatic beta cells, transfers the terminal phosphate of ATP to glucose; Mg2+ is required. This is an irreversible trapping step; it is not the committed step because glucose-6-phosphate can enter glycogenesis or the pentose phosphate pathway. Hexokinase is product-inhibited by glucose-6-phosphate, whereas glucokinase has a high Km and high Vmax and is regulated by glucokinase regulatory protein in hepatocytes.
Anaerobic Glycolysis / Lactic Acid Fermentation Energy Metabolism & Cellular Respiration · Cytosol
Glucose + ATP → glucose-6-phosphate + ADP
Converts Glucose ATP into Glucose-6-phosphate ADP
› Notes
Required cofactors: ATP and Mg2+. This reaction is essentially irreversible and traps glucose inside the cell; hexokinase is inhibited by glucose-6-phosphate, whereas glucokinase has a high Km and is not inhibited by glucose-6-phosphate.
Showing all 2 reactions.
What accelerates and inhibits it
Regulation is pathway-specific, so each context is listed separately
No regulation recorded for this enzyme in the source documents.
Recent literature
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