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, Native (Bacillus sp.)
Applications
This enzyme is useful for enzymatic determination of glucose or creatinine kinase activity when coupled with glucose‒6‒phosphate dehydrogenase.
Appearance
White amorphous powder, lyophilized
Enzyme Commission Number
EC 2.7.1.1
Activity
More than 250 U/mg solid
Contaminants
NADH oxidase < 0.001%; ATPase < 0.002%; Myokinase < 0.002%; Creatine phosphate < 0.002%; 6-phosphgluconate dehydrogenase < 0.002%; Glucose dehydrogenase < 0 .002%
Molecular Weight
68 kDa (gel filtration)
Michaelis Constant
Glucose 8.2 × 10-4M ATP 8.7 × 10-5M MgCl2 1.6 × 10-3M
Unit Definition
One unit is defined as the amount of enzyme which generates 1 μmole of NADPH per minute at 37ºC under the conditions specified in the assay procedure.
Thermal stability
Stable at 55°C and below
Storage
Storage at -20°C in the presence of a desiccant is recommended.
Stabilizers
ATP, albumin, KCl, NaCl
Synonyms
hexokinase (phosphorylating); ATP-dependent hexokinase; glucose ATP phosphotransferase; hexokinase; ATP:D-hexose 6-phosphotransferase; EC 2.7.1.1
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