HK2

Domain

The N- and C-terminal halves of the protein contain a hexokinase domain (PubMed:29298880). In contrast to hexokinase-1 and -3 (HK1 and HK3, respectively), both hexokinase domains display catalytic activity (PubMed:29298880). The region connecting the two hexokinase domains is required for the catalytic activity of the N-terminal hexokinase domain (PubMed:29298880). The N-terminal half regulates stability of the whole enzyme (PubMed:29298880).

Function

Catalyzes the phosphorylation of hexose, such as D-glucose and D-fructose, to hexose 6-phosphate (D-glucose 6-phosphate and D-fructose 6-phosphate, respectively) (PubMed:23185017, PubMed:26985301, PubMed:29298880). Mediates the initial step of glycolysis by catalyzing phosphorylation of D-glucose to D-glucose 6-phosphate (PubMed:29298880). Plays a key role in maintaining the integrity of the outer mitochondrial membrane by preventing the release of apoptogenic molecules from the intermembrane space and subsequent apoptosis (PubMed:18350175).

Pathway

Carbohydrate metabolism; hexose metabolism.

Carbohydrate degradation; glycolysis; D-glyceraldehyde 3-phosphate and glycerone phosphate from D-glucose: step 1/4.

Sequence similarities

Belongs to the hexokinase family.

Tissue specificity

Predominant hexokinase isozyme expressed in insulin-responsive tissues such as skeletal muscle.

Cellular localization

• Mitochondrion outer membrane
• Peripheral membrane protein
• Cytoplasm
• Cytosol
• The mitochondrial-binding peptide (MBP) region promotes association with the mitochondrial outer membrane (PubMed:29298880). The interaction with the mitochondrial outer membrane via the mitochondrial-binding peptide (MBP) region promotes higher stability of the protein (PubMed:29298880). Release from the mitochondrial outer membrane into the cytosol induces permeability transition pore (PTP) opening and apoptosis (PubMed:18350175).

Alternative names

• Hexokinase-2
• Hexokinase type II
• Hexokinase-B
• Muscle form hexokinase
• HK II
• HK2

Database links

• entrezGene:3099
• omim:601125
• swissprot:P52789

Target type

Proteins

Primary research area

Metabolism

Molecular weight

102380Da