Description
A hexokinase is an enzyme that phosphorylates hexoses (six-carbon sugars), forming hexose phosphate. In most organisms, glucose is the most important substrate of hexokinases, and glucose-6-phosphate the most important product. Hexokinase can transfer an inorganic phosphate group from ATP to a substrate. Hexokinases should not be confused with glucokinase, which is a specific isoform of hexokinase. While other hexokinases are capable of phosphorylating several hexoses, glucokinase acts with a 50-fold lower substrate affinity and its only hexose substrate is glucose.
Abbr
Hexokinase (Microorganism)
Applications
The enzyme is useful for enzymatic determination of glucose, adenosine-5'-triphosphate (ATP) and creatine phosphokinase when coupled with glucose-6-phosphate dehydrogenase.
Appearance
White amorphous powder, lyophilized
Enzyme Commission Number
EC 2.7.1.1
Activity
GradeⅢ 150U/mg-solid or more
Contaminants
Phosphoglucose isomerase < 1.0×10⁻¹% 6-Phosphogluconate dehydrogenase < 1.0×10⁻²% Glucose-6-phosphate dehydrogenase < 1.0×10⁻²% Myokinase < 1.0×10⁻²% Glutathione reductase < 5.0×10⁻¹%
Molecular Weight
approx. 82 kDa (by gel filtration)
Isoelectric point
4.1±0.1
pH Stability
pH 4.0-9.0 (25°C, 20hr)
Michaelis Constant
2.3×10⁻⁴M (D-Glucose), 7.7×10⁻⁵M (ATP)
Thermal stability
below 45°C (pH 7.0, 30min)
Inhibitors
Metal ions, p-chloromercuribenzoate, iodoacetamide, SDS, etc
Synonyms
Hexokinase; EC 2.7.1.1; hexokinase type IV glucokinase; hexokinase D; hexokinase type IV; hexokinase (phosphorylating); ATP-dependent hexokinase; glucose ATP phosphotransferase; ATP: D-hexose 6-phosphotransferase