H4502

Sigma

 

Hexokinase from Saccharomyces cerevisiae

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

Synonym:ATP:D-Hexose-6-phosphotransferase, Hexokinase from yeast
CAS Number:9001-51-8
Enzyme Commission (EC) Number:2.7.1.1   ( BRENDA | IUBMB )
EC Number:232-611-5
MDL number:MFCD00131321

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Description

QualityA mixture of isoenzymes.
ReconstitutionReconstitute 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.
Unit DefinitionOne unit will phosphorylate 1.0 μmole of D-glucose per min at pH 7.6 at 25 °C.
Physical formLyophilized powder containing approx. 15% sodium citrate
Biochem/physiol ActionsCatalyzes 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 KM: 0.33 mM
D-glucose KM: 0.12 mM
D-mannose KM: 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: E1% = 8.85 (PI) and 9.47 (PII) at 280 nm

Activators: Hexokinase requires Mg2+ ions (KM = 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)

Properties

typeType F-300
formlyophilized powder
purified bycrystallization
anion tracessulfate (SO42-): free
foreign activityATPase, myokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase and phosphoglucose isomerase ≤0.01%
Gene Informationbakers yeast ... HXK1(850614), HXK2(852639)
storage temp.−20°C

Safety

WGK Germany3

References

referenceKaji, et al. Ann. N.Y. Acad. Sci. 94, 798, (1961) Abstract
 Bergmeyer, H., Grassl, H., and Walter, H-E., Bergmeyer, H.U., ed. Meth. Enzym. Anal. 3rd ed., 2, 222, (1983)