Hexokinase from Saccharomyces cerevisiae 

One unit will phosphorylate 1.0 μmole of D-glucose per min at pH 7.6 at 25 °C, unless otherwise indicated below.

Lyophilized powder containing approx. 15% sodium citrate

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)

Type III

lyophilized powder

glucose-6-phosphate dehydrogenase and phosphoglucose isomerase ≤10%

bakers yeast ... HXK1(850614), HXK2(852639)

−20°C

Bergmeyer, H., Grassl, H., and Walter, H-E., Bergmeyer, H.U., ed. Meth. Enzym. Anal. 3rd ed.,, (1983) 2, 222

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