Hexokinase type I (mitochondrial) (HKI)

Hexokinase type I is an enzyme that catalyzes the first step in glucose metabolism by irreversibly phosphorylating glucose to form glucose‑6‑phosphate, using ATP as a phosphate donor[3][4]. This isoform is predominantly associated with the outer mitochondrial membrane through interaction with the voltage-dependent anion channel ("porin"), which allows it direct access to intramitochondrial ATP[4]. The mitochondrial association enables efficient coupling between glycolysis and oxidative phosphorylation, ensuring rapid energy production and tight regulation according to cellular demands[4]. Mitochondrially bound hexokinase is highly elevated in rapidly growing malignant tumor cells—up to 200 times higher than normal tissues—and drives high aerobic glycolytic rates characteristic of cancer metabolism ("Warburg effect")[3]. In non-cancerous tissues, its primary role is catabolic, introducing glucose into glycolysis for energy production. Deficiency or mutations can cause chronic hemolytic anemia due to impaired red blood cell metabolism[3]. There are several mammalian hexokinase isoforms; however, only types I and II bind mitochondria. Type I remains tightly associated with mitochondria under most conditions and primarily supports glycolysis. Type II has more dynamic localization and can support both anabolic and catabolic pathways depending on its subcellular distribution[2][4]. No specific drugs directly targeting mitochondrial hexokinases are currently approved; however, their role in cancer makes them a subject of ongoing therapeutic interest. If you need structured information for other isoforms or further details on drug interactions or biomarkers as new research emerges, please specify.

Other names

Mitochondrial hexokinaseHexokinase 1HK1