H4502

Hexokinase from Saccharomyces cerevisiae

Type F-300, lyophilized powder, ≥130 units/mg protein (biuret)

• Synonym(s): Hexokinase D, Hexokinasetype IV, ATP:D-Hexose-6-phosphotransferase, Hexokinase from yeast
• CAS Number: 9001-51-8
• Enzyme Commission number: 2.7.1.1 (BRENDA, IUBMB)
• EC Number: 232-611-5
• MDL number: MFCD00131321
• UNSPSC Code: 12352204
• eCl@ss: 32160410
• NACRES: NA.54

Properties

• biological source: Saccharomyces cerevisiae
• type: Type F-300
• form: lyophilized powder
• specific activity: ≥130 units/mg protein (biuret)
• mol wt: 110 kDa
• purified by: crystallization
• storage condition: (Keep container tightly closed in a dry and well-ventilated place)
• color: white
• anion traces: sulfate (SO₄^2-): free
• UniProt accession no.: P04806; P04807
• foreign activity: ATPase, myokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase and phosphoglucose isomerase ≤0.01%
• storage temp.: −20°C
• Gene Information: bakers yeast ... HXK1(850614) , HXK2(852639)

Description

General description

Research area: Cell Signaling

The hexokinase 1 (HXK1) gene is mapped to the Saccharomyces cerevisiae chromosome VI. HXK1 is ubiquitously expressed in mammalian tissues and is abundant in the brain, erythrocytes, lymphocytes, and fibroblasts.

Application

Hexokinase has been used:

• for digesting glucose for measuring glucose content in the root and stem samples of Quercus velutina
• to treat ADP (adenosine diphosphate) solution along with D-glucose to remove the contaminating ATP (adenosine triphosphate)
• in 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer (pH 7.5) for ADP-[13CU]glucose synthesis

Biochem/physiol Actions

Catalyzes the phosphorylation of D-hexose sugars at the C6 position utilizing ATP as a phosphate source.

The rate of phosphorylation varies with different hexoses (pH 7.5, 30 °C).
D-fructose K_M: 0.33 mM
D-glucose K_M: 0.12 mM
D-mannose K_M: 0.05 mM

Yeast hexokinase exists as two similar isoforms, PI and PII (A and B), with isoelectric points of 5.25 and 4, respectively.

Molecular Weight: ~ 54 kDa (monomer)
~110 kDa (dimer)
Optimal pH: 7.5 to 9.0
Extinction Coefficient: E^1% = 8.85 (PI) and 9.47 (PII) at 280 nm

Activators: Hexokinase requires Mg²⁺ ions (K_M = 2.6 mM) for activity. Hexokinase is activated by catecholamines and related compounds.

Inhibitors: sorbose-1-phosphate, polyphosphates, 6-deoxy-6-fluoroglucose, 2-C-hydroxy-methylglucose, xylose, lyxose, and thiol reactive compounds (Hg²⁺ and 4-chloromercuribenzoate)

Hexokinase catalyzes the rate-limiting first step of glycolysis, which involves the phosphorylation of glucose.

Quality

A mixture of isoenzymes.

Unit Definition

One unit will phosphorylate 1.0 μmole of D-glucose per min at pH 7.6 at 25 °C.

Physical form

Lyophilized powder containing approx. 15% sodium citrate

Reconstitution

Reconstitute with water or citrate buffer, pH 7.0. Studies have shown excellent stability during repeated freezing and thawing over a period of at least 30 days.

Safety Information

• Storage Class Code: 11 - Combustible Solids
• WGK: WGK 3
• Flash Point(F): Not applicable
• Flash Point(C): Not applicable
• Personal Protective Equipment: dust mask type N95 (US), Eyeshields, Gloves