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 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) |